That's going to require some scripting, check out the
quake3world.org scripting forum for more information, it may even be worth posting this question there.
Just did a quick test. Create a trigger_count and tag your 4 monsters with it. Then tag the trigger with what you want to trigger, like the door you want to open. Add 4 to the trigger count and that's it. Also remember to use the no_touch or locked keys on the door entity or it'll open anyway if you get close to it.
Cool thanks! And this worked ok? Will this be easy for me to set up as I've never attempted this before..
BTW, I'm remaking 'Dead Simple' from Doom II so I'll post it up when it's all finished, it's gonna contain some new twists

Hopefully I'll be able to find some good sites to host the file as well..
Thanks
It works but if you've never edited with Radiant before I suggest going through some quick tutorials for the basics otherwise you might not know how to access or apply what I posted previously. It's a very simple setup for someone who knows Radiant or Quake3/Doom3 editing.
Hmm, I managed to kind of get it working, I linked everything up, and this is apparent from the lines that indicate this in the editor but when the mosters are killed the door is still shut but I can walk right through it... any pointers?
Thanks for the help so far

Actually it seems to do this even before th monster is killed, now I'm confused

I'd really appreciate some further help with this if possible as it's really got me stumped. I've tried a few different things and nothing seems to work, could you possibly just do a step by step with just two monsters?
Thanks