Who needs to sign the sublease.

[Dave Polykoff]

The Scenario: I have a rental with 3 tenants on the lease. Two of the tenants moved out a few months ago but still pay rent. One of the tenants who moved out found a person to sublease for them. 

Question: Who needs to sign the sublease? Just the old tenant (subleaser), the new tenant (subleasee), and myself (landlord)? Or do the other two tenants need to sign the sublease as well?

Essentially, legally, is the sublease a contract between the 1 tenant and the subleaser? Or do the other tenants need to be involved with that paperwork as well?