Steve,
I had not thought about doing this before, but there is a way to accomplish
what you want.

Run a select of the volumes in the library that meet your criteria and
direct the output to a file prior to your full backup run.  Unfortunately,
select will generate some bogus lines of output, but the BACKUP DB command
may ignore them as invalid volumes.  If it does not then you will have to
use a script to strip off the bad stuff (first 2 lines).

The select looks like this:

select volume_name as " " from libvolumes where .......(picks the ones you
want)...... > DB_volumes

DB_volumes will look like this:
(blank line)
------------
Volum1
Volum1
Volum2
Volum3
.
.
.
Etc.



Then in your backup db command do this:

        BACKUP DB Devclass=3590 Type=full Vol=file:DB_volumes Wait=yes

Hope this helps.  I may consider doing something like this myself.