It would seem that there should be a way, but I have never had this requirement.
The big question is how tell how many records there are...I have never tried to find this out. Without thinking too hard, I would create a counter and for ever detail increment it (there is probably an easier way, but this off the top of my head)
I would add a detail section and it would have a formula in it and I would conditionally suppress it (not OnLastRecord). The formula would look at the counter or recordcount mod 10 and would loop creating lines with dummy record criteria. It would probably need have the crlf added to the line.
Well, this is what I would try. Hope it points you towards a solution.