Modify Open source GSM, CDMA, UMTS and LTE software

We need modification to OpenBTS, OpenBTS-UMTS, OpenLTE and a similar solution for CDMA protocol so that when a cellular devise comes into initial communication with our tower (assume we will be the strongest signal) and sends it registration request we respond that we are the requested carrier (regardless of carrier requested) forcing the cellular device to attach to our network so we can collect the IMSI. This is the first step in what we need to accomplish for a larger project we are working on. Can you provide a solution to this? We are looking for fully documented source code, that compiles, tests, and runs, a modular executable would be preferred (I come from a Window’s environment please forgive my use of terms that don’t apply in the Linux world). We will provide SSH connection to our test setup and our hardware engineers will work with you as needed. For lack of a better description we are building an IMSI catcher on steroids as this part of the project. When UE requests registration with “its carrier” regardless of what carrier that might be, our systems must reply that we are the requested carrier, force the UE to attach to our system.