Anyone here know about rental law, sec. deposits, in MA?

[bicentennial_baby]

Let's say Roomate 1 moves out during the lease...After a month, they request their portion of security/rent deposits back. Landlord will not release $ until apartment is vacated by all tenants, and apartment will not be vacated any time in the near future, as the other tenants are planning to remain for an indefinite number of years. Landlord is legally entitled to not pay Roomate 1 anything at this point in time. So, it's now in the hands of roommates 2 & 3. Does anyone know what the legal obligations of roommates 2 & 3 are, re: this matter, if any? Are they req'd to pay Roommate 1 now, or can they legally sign an agreement with Roommate 1 saying that they will be reimbursed at the time when the apartment is vacated and all deposits returned?

If anyone knows anything about this, thanks in advance :)

[bottomofthehill]

1. Did roommate #1 leave before the lease was up?

[bicentennial_baby]

2. Yes

Actually, about 2 weeks after the new lease was signed.