GSM DoS or conditional access project

Hi I wonder if there is a way to develop a Denial of Service or Conditional Access system for a GSM network based on Osmocom. The idea is to develop a commercial product intended to be used to limit unlawful communication in prisons or correctional facilities. My investigation is that this is a kind of worldwide necessity as inmates use smuggled mobile phones for criminal activities (I live in Central America and constantly see news that confirm this is urgent requirement). Currently there a few options available to achieve this purpose: 1. Government authorities require telecom operators to reduce radio signal in the vicinity of confinement facilities2. The use of radio jamming systems to propagate a noise signal3. One or two commercial solutions like iNAC Managed Access from Tecore (a very clever and patented technology) I imagine a solution based on Osmocom as a base station simulating a roaming area in the correctional facility area, for authorized users, dummy network should appear as a FPLMN but for illegal users the fake network must grant access entering driving them into a dead end network with no communication. However I see there are several flaws for this aproach: one is that inmates could set their mobiles to manual network selection and connect themself to commercial mobile networks but I hope this could serve as a ground for further discussion. I will appreciate very much your comments. Regards,