Leaders in the two rival golf course development groups in Edgartown said yesterday that they will merge memberships and stop competing with each other.

Owen Larkin, the managing partner for the Vineyard Golf Club, confirmed that he has signed an agreement to offer guaranteed membership to every member of the Meetinghouse Golf Club Inc. In return, the leading developers for Meetinghouse have agreed not to reapply for permission to build an 18-hole golf course on the MacKenty family property along the Edgartown Great Pond, Mr. Larkin said.

“It’s not exactly a merger,” Mr. Larkin said yesterday. “We are not merging anything — we are inviting their members to become members in our golf club.”

“Maybe joining is the right word —  we are joining for the benefit of the community,” said M. Anthony Fisher, an investor and founding member of the Meetinghouse Golf Club.

The agreement ostensibly clears the way for Vineyard conservation groups to make an offer to buy the MacKenty land, but both Mr. Larkin and Mr. Fischer admitted that they are not involved in the negotiations, which are complicated and involve three separate members of the MacKenty family plus the original Meetinghouse developers.

“There are many different parties there, and we are not becoming involved in that,” said Mr. Larkin.

Meetinghouse developers include Richard Friedman, a Boston real estate developer who owns a home on the Oyster Pond, and Rosario and Barry Lattuca, a father and son team from Natick.

Mr. Larkin won permission from the Martha’s Vineyard Commission three months ago to build an 18-hole golf course on the old Vineyard Acres II subdivision off the West Tisbury Road in Edgartown. A month earlier, the commission rejected a plan by the Meetinghouse Golf Club for an 18-hole golf course on the MacKenty land.

The Meetinghouse developers announced recently that they would resubmit a new plan. But yesterday Mr. Larkin said the agreement to offer memberships to the Meetinghouse Golf members was signed late last week. The memberships will be discounted, although Mr. Larkin declined to say how much. Memberships in the Vineyard Golf Club are now selling for $225,000. If all the Meetinghouse members join the Vineyard Golf Club, the club will be nearly fully subscribed, Mr. Larkin said.

Mr. Larkin also said some Meetinghouse members will be invited to join the board of directors for the Vineyard Golf Club. He said the business terms between the two groups are confidential, but he did say that the Vineyard Golf Club will make some contribution toward the costs incurred by the Meetinghouse group.

Mr. Larkin credited Mr. Fisher for bringing the two groups to the table: “It was Tony Fisher who said, ‘Let’s see what we can do to make this work for the community’ — and that is the driving motivation behind the discussion.”

Less clear is the nature of the talks now under way for a possible conservation purchase of the MacKenty land.

Tom Chase, the bioreserve manager for the Vineyard and Nantucket for The Nature Conservancy, confirmed that he has been involved in the talks.

“The Nature Conservancy has been in discussion with the developers for several weeks now — we, of course, want to be respectful to both the landowners as well as the developers, but we stand fully prepared to pay the same price for the same land — we may even be able to offer an additional tax advantage to the seller,” Mr. Chase said.

“The primary concerns are to restore the land and protect the pond — this is a great moment and we are extraordinarily grateful to the developers for their willingness to work with us.”

The sale price of the MacKenty land is now reported to be $11 million.

Any conservation purchase of the MacKenty land is complicated by the family’s relationship with the developers, who had two purchase options for the land — one hinging on the development of a golf course and a second option hinging on a residential subdivision.

In the event that an outright conservation purchase of the MacKenty land cannot be accomplished, a backup plan is reportedly on deck to develop a nine-hole golf course and gift some 100 acres to conservation.