We have two TSM servers with one that backs up all nodes
on the network (Intel and AIX) and the other that backs
up data specifically written to an OnDemand server (historical,
legal stuff that is kept for 6+ years).

Is it possible to cause the temporary stuff, the files
sent to OnDemand today that are not yet off-site in
6 year storage, to the other general purpose TSM so the
files do get preserved and off site in some way in case
something drastic happens?

Does this make sense?

I'm not trying to change OnDemand, but rather temporarily
send files from one TSM to the other.

Mike