Multiple Mail policy

This is the sinario,
We are running Win2k3 Standart with Exchange 2003 Standart.
We want to be able to allow all users to have a maximum default sent/recieve of 7mb.
We also want to allow special users to have a maximum of 100 mb sent/receive. What do I need to do to make this work?

I have looked all over but was not able to find the answer.