Keep Kahala Kahala.

That’s the essence of a lawsuit seeking to block a local developer from putting up three two-story duplex homes on a large beachfront lot along one of the toniest residential streets in Honolulu: Kahala Avenue, where multimillion-dollar mansions rule.

More than a dozen Kahala residents have banded together in an effort that is something like an urban version of what more rural residents on Oahu’s North Shore have done to keep development in check through groups that champion the slogan Keep the Country Country.

On Kahala Avenue the six planned homes don’t appear to stand out, as depicted in an artist’s rendering. But some neighbors believe that what amounts to multifamily condominiums will usher in a wave of similar projects and ruin the neighborhood.

Lucinda Pyles and the nonprofit Friends of Kahala filed the lawsuit in state Circuit Court earlier this month, aiming to stop Alexander &Baldwin Inc. from developing the homes on a 1.3-acre parcel at 4607 Kahala Ave.

“This issue has significant implications not only for the character of Kahala’s century-old single-family residential neighborhood, but for other mature single-family residential neighborhoods as well,” Pyles said.

Richard Turbin, chairman of the Waialae-Kahala Neighborhood Board and a neighbor of Pyles, said he and about 20 other area residents are members of the nonprofit formed to defend their community.

“It may be the finest residential beach community in the Pacific,” he said. “We just want to keep it that way. We don’t want to lose it to townhouse condo development.”

Previously, many residents on the street regarded Honolulu-based A&B as a savior. That was because the company bought 30 residential properties in 2013 from Japanese billionaire Genshiro Kawamoto, who had acquired the real estate over several years and left most of it in shambles after crudely breaking down walls and filling in swimming pools. Kawamoto demolished some homes while others became vandalized eyesores.

A&B renovated some of the former Kawamoto houses, demolished others, cleaned up lots, and to date has sold 21 of the 30 properties for close to $120 million.

But at 4607 Kahala Ave., A&B aimed to enhance its financial return by building and selling six homes.

A&B projects it will cost $40 million to $45 million to develop the homes, each of which would contain about 5,000 square feet of single-level living space and a pool.

The developer said in a final environmental assessment accepted by the city Department of Planning and Permitting in April that its project will revitalize the neighborhood by returning residential use to the site now occupied by overgrown grass and remnants of prior homes. A&B added that the design elements of its project — which resembles three duplex mansions — are consistent with the surrounding neighborhood.

Pyles, however, disagrees and criticizes A&B for seeking to profit off a neighborhood that she and her husband, John, have called home for four decades.

“Our children grew up here, and our grandchildren play in the same yard, enjoy the same beach as our sons did,” Lucinda Pyles said in a letter to DPP objecting to A&B’s plan. “A&B is looking for a return on investment. We hope to be living here 20 years from now, God willing. With all due respect, A&B is not looking to be a neighbor now or in 20 years.”

Pyles lives about 10 properties away from A&B’s development site in a 3,543-square-foot home that property records say was built in 1928 and bought by Pyles and her husband in 1975.

To be sure, the character of Kahala, especially along Kahala Avenue, has been long evolving and contains a mix of historic smaller homes, modern mansions and large lots formed by wealthy buyers consolidating what used to be two or more single-family residences. Some properties have more than one dwelling.

But Friends of Kahala, which also includes local developer Don Eovino, said A&B is likely kicking off a wave where large estates will be converted to multifamily dwellings shared by multiple owners.

“We’re facing a future prospect of a wall of condominiums along the beach,” Turbin said. “I’ve seen this type of thing when I’ve visited Southern California, and I hope we can stop it before it spreads to oceanfront areas on Oahu.”

In the lawsuit, Friends of Kahala contends that A&B failed to analyze “cumulative impacts” of its project that state environmental regulations say include reasonably foreseeable actions by others.

The lawsuit, filed by local attorney William W. Saunders Jr. against A&B and DPP, argues that similar housing projects encouraged by A&B’s project constitute such a cumulative impact.

Friends of Kahala claims in the suit that allowing A&B’s project will inspire nonresident speculators, particularly Chinese investors, to convert single-family residential properties into luxury condos in Kahala and other neighborhoods.

The suit said such projects will inflate property values and have a “seriously detrimental impact” on the character of Kahala and surrounding neighborhoods.

Lance Parker, president of A&B’s real estate subsidiary A&B Properties Inc., said in a statement that the project doesn’t harm the community.

“While we understand the concerns of these Kahala homeowners based on the several meetings that we’ve had with them to present and discuss our plans, we believe that our project is consistent with the character of the neighborhood, and it complies with applicable ordinances and regulations,” he said.

The project site is zoned R-7.5, which is a residential classification that permits three types of dwellings: single-family homes, two-family detached homes and duplexes.

A&B said the size of its lot, 58,207 square feet, allows up to seven homes given that the city’s land use ordinance for R-7.5 zoning allows a single-family home to occupy a minimum of 7,500 square feet of land. The ordinance also specifies that 14,000 square feet is required for a two-family detached home, and 7,000 square feet is required for a duplex under such zoning.

Previously there were two homes on the property.

Some Kahala residents raised an issue with the neighborhood board over A&B’s plan possibly running afoul of Kahala Community Association covenants that include a prohibition against more than one home on a lot. But a consultant for A&B said that prohibition doesn’t apply to the company’s lot.

A&B estimates that planning and permitting could be done by 2017 to allow construction to be finished in 2019, though Friends of Kahala hopes that A&B will alter its plan.

“To squeeze in six luxury condominiums in huge two-story buildings is just too much,” Pyles said.