With a September deadline to meet state financing conditions for the regional high school building project, all six Island towns agreed Wednesday night to begin talks on how to apportion their shares of the cost.

Meeting was held in person and over Zoom. — Ray Ewing

The accord came at a rare summit meeting of the high school committee and select boards, held simultaneously on Zoom and in the high school cafeteria.

“It’s exciting that we are in this new chapter,” said school committee chairman Amy Houghton.

There’s no estimate yet of how much the high school project will cost, though $100 million has been used as a round number for discussion purposes.

An all-Island committee of 13 — the town administrators, one member of each select board and superintendent of schools Dr. Matthew D’Andrea — is charged with arriving at a six-way construction funding formula that’s acceptable to each board.

The Massachusetts School Building Authority notified the school district earlier this month that it will contribute up to 38 per cent of construction costs, as long as the Island towns are able to show by this September that they can raise the rest.

But a new wrinkle from the state education department is requiring the district to also revisit the original six-town accord that predated the regional high school’s construction in 1959.

As Ms. Houghton began to explain the issue during her open remarks Wednesday, Edgartown select board member Arthur Smadbeck seized the floor to object that the meeting agenda included not only the building project, but that longstanding regional agreement governing how the towns divide the high school’s operating expenses every year.

Edgartown select board member Arthur Smadbeck objected to the meeting agenda at the outset. — Ray Ewing

“What we’re going to have to do has nothing to do with the agreement,” Mr. Smadbeck said. “What we have to do, as six boards of selectmen, is to come up with a formula to pay for the balance of the school [building].”

As Ms. Houghton asked to finish her remarks, a visibly perturbed Mr. Smadbeck continued to speak over her.

“On top of trying to figure out to divide up the cost of this building, to try and throw anything else in at this point would be a distraction,” he said.

But leaving the regional agreement untouched is not an option, Ms. Houghton told Mr. Smadbeck after he had finished, because it has to be rewritten in order to comply with the state’s latest rules on such pacts.

“I understand that this is a frustration for you, but what I need you to understand is what we have been given as guidance from the state,” she said.

“In order to approve an amendment to our regional agreement, our regional agreement needs to be up to snuff with what the state guidelines now are asking for.”

Furthermore, Ms. Houghton said, school leaders learned recently that all but one of the funding amendments to the original high school agreement of the mid-1950s were never recorded with the Massachusetts Secretary of State.

“The state has a regional agreement that is not the regional agreement you have in front of you,” Ms. Houghton said.

State education officials have agreed to let the unrecorded amendments stand, Ms. Houghton said, on condition that the entire agreement is rewritten and resubmitted.

Chilmark select board member James Malkin (left) and up-Island school committee member Robert Lionette. — Ray Ewing

“They have given us a checklist of those things that need to be in the regional agreement,” she said.

The required alterations do not affect the towns’ funding split, Ms. Houghton added.

“They have nothing to do with funding, by and large, but because we are a vocational school [and] because we provide transportation out of the high school . . . there’s new guidance from the state,” she said.

If the regional pact isn’t updated to reflect the new requirements, Ms. Houghton continued, “we run the risk of having the state say ‘We don’t accept this addendum to your agreement.’”

And that means the district would not be eligible to borrow the money it needs for the high school building, thus losing the MSBA grant, she said.

Ms. Houghton recommended that while the committee of 13 is working out the construction funding formula, a subgroup of school committee members should concentrate on rewriting the regional agreement language to meet the state’s requirements.

The district then will submit the revised agreement and the construction funding amendment together, she said.

“We’re not going to the state twice,” Ms. Houghton said. “That’s why we want to make sure the funding is buttoned up as soon as possible.”

The timeline is tight, she added, because the district’s drafts must be approved by the state education department before the MSBA deadline in September.

Select board members from all six towns agreed to the plan, with May 15 as an initial target date for the 13-member committee’s decision.

“Let’s see if we can get it done,” said Chilmark board member James Malkin.

“I’m with Jim: I would get in a room tomorrow,” Mr. Smadbeck said.

“We know the complications,” Oak Bluffs board member Jason Balboni said.