How to distingish between two incoming channels

I wish to have an secretary operate a phone for two departments. Each is on its own PSTN number but I want each FXO to ring the same telephone. This is obviously straight forward to do, but I need the secretary to be able to distinguish between the two channels by having them ring differently.

Is there anyway I can change the ring pattern/tone based on the FXO which causing the phone to ring ?

Thoughts please

channel/did routing with CID prefix and/or Alert-Info for different rings.

Many thanks for your reply.

Could you possibly give me an example that would work for X-Lite; or alternatively point me at some documented examples.