ROCKLAND, Maine — A looming referendum in Rockland on whether the city should start the process of withdrawing from the regional school district is worrying neighboring Thomaston.

Thomaston selectmen held a closed-door session Monday evening with town attorney Paul Gibbons to discuss strategies in response to the possible withdrawal of Rockland.

Greg Hamlin, chairman of the Thomaston Board of Selectmen, said the effort by some Rockland board members was putting the cart before the horse.

“They’re messing up the works,” Hamlin said.

He pointed out that after several years of not doing anything to consolidate schools in order to save money, the district administration is prepared over the next two months to unveil a plan that would do that.

The possible withdrawal of Rockland from Regional School Unit 13, however, would throw a monkey wrench into any consolidation effort, he said, because the board would instead be focusing on how to deal with the possible withdrawal of the largest community in the district.

“That’s where the big savings would come,” Hamlin said of consolidating schools. “The fear is that the withdrawal could lock things up. I hope not, but that could happen.”

RSU 13 has two high schools — Oceanside West in Thomaston, which serves eighth and ninth graders, and Oceanside East, which serves 10th through 12th graders. The district also has two middle schools — one in Thomaston and one in Rockland. There also are one elementary school in each of the five municipalities that make up RSU 13 — Rockland, Thomaston, Owls Head, South Thomaston and Cushing.

Hamlin would not discuss details from the executive session, but said he expected the town would try to present information to the public about the possible impact of Rockland’s withdrawal prior to the referendum vote on Nov. 3.

Rockland RSU 13 board members Esther “Tess” Kilgour and Donald Robishaw Jr. were among the organizers who filed a petition with Rockland with sufficient signatures to get the item on the November ballot.

Another vote would have to be held in Rockland before withdrawal could occur and the process, if pursued, could take more than a year.

Kilgour said earlier that if the referendum is passed, it would simply allow Rockland to gather information on the advantages and disadvantages of breaking away from RSU 13.

St. George withdrew from RSU 13 last month following a multi-year effort and a November 2014 vote in that town.

Of the projected enrollment of 1,730 students in RSU 13 for the upcoming school year, 725 are from Rockland.

The petition that forced the referendum was signed by three Rockland school board members — Kilgour, Robishaw and Nancy Jeffers — as well as three city councilors — Mayor Frank Isganitis and Councilors William Clayton and Valli Geiger. Two former superintendents — Donald Kanicki of the former SAD 5 and Paul Luttrell of the former SAD 50 — also signed the petition. RSU was created from the consolidation of SADs 5 and 50.