Yes, PoolExpert does support that pool type.  To use it, connect in admin mode to your pool and go to the General rules section.  Put a checkmark in the “Use the Active/Reserve feature”.  Once saved, you will see another link appearing in the left nav bar called “Active Roster Size”.  Use this page to define your roster rules.  PoolExpert will after take care of respecting those rules during trades and roster changes.