autoloader 1/8 all servers, each day problem

[Jimampm]

Hello, I am currently trying to setup a backup job and am having trouble pointing the correct tape/media to the correct job.

Using the autoloader 1/8
Veritas 12.5
Windows Server 2003

Trying to setup the following job...
1 full backup of all servers each day for Mon - Sat.
Each day I would like the back up to use a new tape, then overwrite that tape the following week.

As of now, when I try to make a backup job it grabs a random tape and overwrites it, which gives me no previous back up.

Thank you for your time.