Orach Chayim 153 (15) says that a person cannot forbid with a vow (assur) his part of the synagogue or the books in it. If he did make such a vow, it is ineffective. MB  explains that this is a decree of the Geonim to prevent someone taking such a vow in a quarrel and thereby forbidding all the shul on everyone because we cannot identify which part belongs to the person who took the vow (ain bereiro).
Can this ruling be extended to any thing held in joint ownership by a number of people? (There is a (true?) story of a yeshiva bochur who forbad his portion of the cholent with a vow and was told he was expelled. He explained to the Rosh Yeshiva that he had never wanted to be expelled by this action and the Rosh Yeshiva annulled his vow. If the ruling above was extended, it may not have been necessary to find a way of annulling the vow.)
Can a person forbid with a vow his portion of a jointly owned item?