For example a Nurse call system connects via a SIP trunk to the PBX. I want the nurse call system to only be able to dial a specific extension range.
The second system is a communications system that staff members wear on them that works wirelessly. There is a SIP trunk to that system and I would like to have staff wearing the devices be able to call internal extension and make outbound calls via our PSTN SIP trunk.
Does that help, or make it worse?
I am familiar with another Asterisk based system that you set inbound routes per SIP trunk so you can create individual routing for calls that come from that trunk.