If the tape is full, but has not passed it's retention date, then you must provide a different tape
if this worked previously, but now does not, your data may have grown to the point that it no longer fits on one tape. You will probably have to...
There is a way, but it is not very elegant
Every time you swap tapes in the magazine, reinitialize/relable them in the order that you want them used
Backup Exec will then use them in the order that they were labled.
(Bear in mind also that...
Is this because I'm doing three jobs for the same tape in the same day?
Sounds more like you are overwriting the tape each time a job runs
You should make the first job that writes to a tape (the first of the day) Overwrite, and all the others A...
This certainly is physically possible if you have enough disk space, but may very well be illegal - at least in the US
Better check with your corporate legal department and have them refer to the Sarbanes-Oxley act of 2002