[robertthebard]

Yes, all you have to do when you set up the door is give it the tag, or maybe the resref of the key you want it to use. You could even set variables on the key, and have it open doors as you come to them, creating a master key. I'm way rusty as to how to go about this though.

Edit: Ok, I thought about this for a minute, and it would be the tag of the key, and the script would just be a simple check/set blurb of a thing, with only the tag of the door needing to be different.

Not a script:

If GetLocalVariable(xxxxx)=1
Return;
SetLocalVariable(xxxxx)1

Ok, way rusty, but you get the idea. Each door would have it's own variable, which could just be the tag of the door. It would then set the variable on the key, probably OnUse of the door, and presto, master key.