it could be that 8.5 doesn't have this option to do a group sort / top n.
if you're looking for the data to spill into a new label then that won't work for you anyways.
here are some options:
a) the group itself needs to repeat in order to have another label available. the only way to do something like this in 8.5 is for your database administrator to create a stored procedure that groups the sopnumber data into sets of N values.
e.g. each group would only have at the most 5 tracking numbers. if a sopnumber had 12, then 3 groups would be created by the stored procedure, e.g. INV0001234_a, INV0001234_b, & INV0001234_c this would be required to create the correct number of labels and to ensure that all data from each sopnumber was eventually displayed.
once a stored proc is created to break up the data into these groups, you need to create a new report off of the proc and use this new grouping field to base your group on.
b) another option would be based on whether or not your database had a specific field that indicated a running total counter for the tracking numbers which was reset every sopnumber. e.g. if sopnumber INV0001234 had 4 tracking numbers, there would be a field that indicated 1,2,3,or 4 depending on the record.
c) another option would be if the stored proc simply brought back the data that you have as well as a running total / counter that indicated / counted in a manner similar to the above. this may be a better option than a) or b)
-jamie