OK, back in the lab, and with access to all documents, we find, as we expected, PEPPERZ is absolutely correct.
The Feature Reference says:
For Release 2.1 and later systems, an extension can be assigned as a member of more than one
Calling Group and the member can log in and out of individual Calling Groups or in and out of all
Calling Groups. For Release 2.0 and earlier systems, an extension can be assigned as a member
of only one calling group.[/color blue]
So, that means you will need an upgrade to make this happen.
This may be able to be arranged....