Putting up a simple wooden frame with chickenwire outside of our office window seemed to help, so they could get out some. We still use one even though we are down to two cats for the first time in my life.:-)We call it the "chicken coop" but it's really an unglorified cat run.

There are also some herbal calming products which have helped with the ones who are nervous. I think you can get them at the bigger pet stores, but also at Drs. Foster and Smith online.

We had to be religious about not leaving clothing on the floors and closing doors, as you say, and trying to give them each the attanetion they seemed to need.

Good luck and how about one of those reduction candles?"-)