socket problem

Hi, I want to run two different nanoBTS s with different network parameters(MCC, MNC), at the same time. I think it is not possible in one configuration file. Instead, I tried to run two bsc_hack with different configuration files at the same time on the same PC. However, I got a socket problem for second bsc_hack (Could not bind socket. Already in use.) . What should i do to solve this. Should i modify the code or do something else. Thanks. Jason Mercury