Sql send larger backups to tape and smaller backups to disk

I saw some people discussing setting up TDP backups so that if you had a single sql database server that had say 100 databases, 2 of them are over 200GB, a couple around 30 or 40GB, and the rest under 10.

What i would like to do is use a different management class for the databases that are over 50GB to send them directly to tape instead of our diskpool.

I don't want to specify the database though because if one of the smaller databases gets to 50GB, i want it to happen automatically.

the database sizes i used above are just an example not the real sizes of the databases.

Any thoughts on how i could accomplish this?

thanks