Jigglywiggly,
I'm adding backup to mrunkel's voice of reason here.
By altering sources.list, leaving the file altered, and not reverting to using ONLY Untangle repositories. When the server auto upgrades at 2am the following morning, it will pull a pile of updates from the Debian repositories that aren't compatible with Untangle. Untangle is based on Debian 5, it is NOT Debian 5.
Also, Untangle by definition is a management system. You've just installed a SECOND management system. They will operate in conflict. So I repeat, this is a bad idea. But, it is open source, you're free to hang yourself as you please. We're just trying to explain this to you before you find yourself in a train wreck, and wondering why these forums aren't helping you.
As for the staggered upgrade, it's called bandwidth. When you have a few thousand Untangle installs out there trying to auto-upgrade, you don't just open the flood gates. That's a good way to knock out your own data center.