using less than one tape per run?

[Scott Mcdermott]

I currently have a 21-tape changer I'm using and it seems
that if I use less than one tape, it doesn't matter, even if
I only use one block on the tape, AMANDA still goes to the
next tape for the next run.  This limits me to a 21-day
tapecycle if I'm not mistaken.  Any way around this?