I want to achieve the following schema:

1. Accept an initial invite
2. Create separate dialog to different SIP server (probably with some headers from point 1)

3. Wait until that different SIP server will complete dialog.

4. Based on result of point 3, transfer invite from 1 to the next steps or decline a call.
The problem I've experienced - how to create a separate dialog and control it inside main dialog?

Thanks a lot!