This won’t be a problem at all. Everything is dependent on your backup software. If you can’t afford to buy any software to use with your DAT drive, you can use NT backup for the backup jobs on each server and schedule a copy job on each of the servers to move the backup files to the server with the DAT drive. I assume you are in a Windows environment, but if not, you should be able to do all of this in a Linux environment with even fewer complications.
If you buy the Dell 110T, it will be even easier. Galaxy Express is from CommVault. I have used the full blown CommVault Galaxy software before and was very impressed with it. The Galaxy Express is simply a lightweight version of it. It should come with the ability to backup 5 systems, so you won’t have to worry about extra licenses. As long as you “append” each backup job to the single tape in the Dell 110T drive, you will be fine. Or, if you are backing up a lot of data, someone will have to watch the job and swap out tapes as needed.
This shouldn’t be too difficult to do. The Galaxy Express software will come with some decent training material. Here’s a link to a PDF file from CommVault about Galaxy Express: http://www.commvault.com/pdf/DS_GEX_Overview.pdf