Members of the Sixth Form Colleges Association, APVIC, will now not link up with the new body before the autumn.
The decision, taken at an emergency meeting of APVIC this week, comes after moves by the association for a "fast-track" route to join the merger of the Association for Colleges and the Colleges' Employers' Forum were stalled.
The CEF and AFC agreed last week to press on with the merger, but both said APVIC should wait until the election of the board of the new body to launch negotiations on joining the partnership. The results of subsequent talks are unlikely to be put to sixth-form colleges until a meeting in the autumn term.
In the meantime, speculation is mounting over the composition of the new board, due to be elected in June. Both AFC and CEF have drawn up unofficial slates in the knowledge that the board's composition will dictate the result of the high-profile contest for the leadership of the new organisation.
While it prepares for negotiations with the new board, due to meet for the first time on July 9, APVIC has suspended its hunt for a general secretary. It advertised the vacancy after deciding last December to create a paid post.
At that time, APVIC leaders were keen to stay out of the merged body, fearing sixth-form college interests would be swallowed up. However, they changed tack amid concern that up to 40 of their members would defect to the new organisation, marginalising APVIC .
The association issued a list of demands, including a call for an increase in the sixth-form college seats on the new board from one to four, a full-time staff member in the new company to look after the interests of 16 to 19-year-olds, and the creation of a sixth-form college special interest group.
They also said that, since sixth-form colleges would continue to use their own employers' forum for pay and employment matters, they should pay a reduced membership fee. The APVIC leadership denies rumours that the proposal - guaranteed to infuriate general FE colleges who are already sore over subscription rates - is understood to have been dropped.
The AFC, which has approaching 30 sixth-form college members, is understood to have been more favourable to APVIC's overtures. Chief executive Ruth Gee told members at last week's meeting the new board would be most appropriate body to deal with the application, but added: "I would hope that it may be possible to have some negotiations conducted between now and July in order that recommendations can be put to the new ABC board as soon as possible."
APVIC chairman Howard Clarke, principal of Stockton Sixth Form College, said: "There is good will on both sides to continue to talk in the interests of the colleges and the sector as a whole."
The association will not have to carry out a written consultation of members. Its rules allow it to consult by reconvening the emergency meeting suspended this week.
Nick Brown, principal of Oldham Sixth Form College and a member of the APVIC faction which pressed for participation in the merger from the outset, said: "Both the AFC and CEF are keen to get the sixth-form colleges in but the time scale is longer than expected."
Formal moves to the AFC-CEF merger were nodded through at meetings of the two organisations in less than an hour with no visible signs of dissent. However, some colleges are discontented with proposals to set subscription levels at a rate likely to save the average college belonging to both current organisations 15 per cent of its present fees.