I sent them a certified letter this am to all parties involved (students and co-signers). Basically I told them that they are responsible for rent until august 31. If they insist on breaking the lease I will show the house to prospective tenants but they are responsible for rent until i find someone else and the cost of that activity. I feel better now that I have responded and am confident if I have problems renting it that I will recoup my losses from their breach of contract in small claims court. Thanks for all the input.
TP