When setting up a Fee Allocation Rule, you specify which attributes a pupil must have in order for the fee to apply. One of these attributes is membership of a custom group. It would be extremely useful to be able to explicitly exclude pupils who are a member of a custom group.
An example is if a different charge code and amount is used for a subset of pupils. Having the ability to exclude based on group membership means that we could have one rule that applies to a set of pupils where they are IN the group, and a different rule to applies to a set of pupils where they are OUT of the group. At the moment, we have to have two groups - one for IN and one for OUT - and do a lot of cross-checking to make sure that pupils are always in one and only one of the two groups, which is a manual process.