Using Excel 2007 as roster...

Hey guys,
In the past I've had a lot of help from you guys in building this spreadsheet.
Right now I want to add an "Unavailabilities" section to help me in rostering.
I have inserted a new slide marked "Availabilities". I want this to be the basis for rostering. At present each employee are available for all the time, but I want the 1st sheet "Roster" to be able to interact with that sheet.
For example, If No. 1 is unavailble on Monday's after 5, I would like Excel to warn me/stop me if I was to try rostering this person after 5.
If you can work out a way to do this I would greatly appreciate it.
Also, anyone that has any suggestion's on the improvement of this worksheet feel free. I have been working on this for a number of months now and so far am very happy with the product so far but there is always room for improvement!
Thanks in advance,
Regan

24 Views and still no reply? Has no one got any help??

Perhaps I worded this question wrong? No one can help me?

Just bumping this up... It's still bugging me. Hopefully you (the reader!) can help!

Last chance you guys. Any high tech's or Moderations willing to offer a hand?