I don't think I explained my problem well enough.
I have a datatable. Each row has the following columns
[PersonID] [PersonName] [PersonTypeID] [PersonTypeName]
So when I group by PersonTypeID, It shows the PersonTypeID inside the group description
But I want to display the PersonTypeName inside the group description (but I don't want the grouping to use the PersonTypeName to filter, because it takes much longer to filter a string than an integer)