Multi-mode endpoint in a communication network system and methods thereof

A terminal gateway, comprising:

• at least one communication interface;
• at least one processor coupled to the communication interface;
• and
• at least one storage element storing instructions for execution by the at least one processor, the instructions comprising:
• instructions executable to register a first communication terminal coupled to the terminal gateway with a first communication server and to register the first communication terminal with a second communication server differing from the first communication server;
• instructions executable to establish a first communication session between the first communication terminal and a second communication terminal by exchanging signaling with the first communication server;
• and
• instructions executable to establish a second communication session between the first communication terminal and a third communication terminal by exchanging signaling with the second communication server during the first communication session.