Tower Defence waves loading

Hey guys!

Since I’m not the first guy in history to program a Tower Defence, I thought I might ask you how you solved this, or would have solved it:

Loading waves in a reusable manner. I really don’t want to have to reload a file, or reprocess anything really. I’d like to be able to load and process the data, and then use it several times.

What I thought I’d do, was to interpret some simple simple text-document that feeds a Queue of creeps. This Queue will then be used to grab a Creep, and insert it into the world - thus, creating a wave of Creeps.

There’s a problem here, though. I can’t modify the original Queue, because that would ruin any playthroughs of the same level. I only want to have a single loading screen.

So… how would you solve this?