How to set up an atypical dependent drop-down

[AshleyMF1983]

Nevermind, please delete!

 

[bobhc]

You may find what you need here, probably the best site for drop down.

http://www.contextures.com/xlDataVal02.html

 

[Faseeh]

You may simply use highlight duplicate values, if you have one date for two employees then highlight duplicate values will simply highlight the duplicate case..

See attached file for example.