distribution on certain days
 

I have a list of people distributed on week days, such as:
Monday: alex, rose, lisa
Tuesday: george, gary, mitch
wed: ......
Th:.....
Fr:....

I would like to create a dist group say named "meeting" and when i send email to "meeting" address on monday, alex, rose, lisa will receive the mail only and if i send on tuesday george, gary, mitch will receive the mail only.....
Any suggestions are highly appreciated...
Thanks...