Duplicate IPs for Radius Clients with different secrets

Hi, I'm wondering if someone can point me in the right direction. I want to list radius clients with the same IPs (and different shared secrets). This would let me use freeradius among multiple offices, where each could use the same IP addresses for the radius clients. I need something very dynamic; manually creating virtual servers in the config file won't work well. Right now I'm using v1.188.2.4.2.14 Thanks! Eric