A system, comprising various methods and apparatus providing a transparent communication session setup and control for communication sessions involving different communication capabilities, is disclosed. The system receives a request for a communication session at a proxy apparatus, the request being originated from a first subscriber to the communication session using a first group of terminals. The system identifies at least a second subscriber to the communication session using a second group of terminals. The system evaluates types of communication being available for the first group of terminals and at least the second group of terminals on the basis of the request. The system sets up terminal sub-sessions from the proxy apparatus to the first group of terminals and to at least the second group of terminals according to types of communication being available for the first group of terminals and at least the second group of terminals.