7200 and 7100 networked, one is 2XXX, other is 3XXX. Is it possible to move extensions from one side of the 2 networked systems, to the other and keep the same extension number and DID (pretty sure they will need a new extension in the same range as the second system, and I will just point the DID to the new extension).

They are pretty hell bent on keeping the extension numbers, but I don't think it is possible.
Thoughts?