I just had an afterthought that could be independent of the data, which is to create an incrementing formula using WHILEPRINTINGRECORDS. It would take some playing with, but you could initiaise it with 1 and then have the increment in the Group footer and then a test somewhere that says when it gets bigger than 10 then stop.
I haven't tested this at all, but share it as a wild idea. What I cannot see is how Crystal would know what was in each group and therefore how and when it would stop the Group and so cause it to increment and go on.
So this may or may not work, but I thought I would toss it out there for comment anyway.
Many thanks,
Caspar