1. If you have a stand-alone tape drive, just put the tape in on the correct day!
2. If you have an autoloader/tape library, partition the library into 2. 1 partition contains the slot for the tape you explicitly need to use for a particular backup on a certain day, and just make sure that tape is in the correct slot before targetting the job at it, and the other partition contains the rest of the slots for other backup jobs.
Have a read at this article by pkh as well - https://www.veritas.com/community/articles/must-mondays-backup-be-monday-tape
That article explains why its a better option to let BE manage the tapes instead of using a specific tape for a specific day.
If you still want to go ahead with your plan, then "partition" your tape library.
It's much over muchness really. I partioned libraries/autoloaders and never had an issue. Actually neither did Backup Exec. Some prefer not too...it's whatever suits you best.