flatfile schema logic


I need help creating a schema for my flatfile. I have problem parsing repeating records in the file.

This is the file:

100 (header)
-110 (max repeat 5 per 100)
–120 (max repeat unlimited per 110)
—125 (unlimited per 120, NOT MANDATORY)
—126 (unlimited per 120, NOT MANDATORY)
—127 (unlimited per 120, MANDATORY)
900 (tail)

My problem is that I cannot find out how to loop 125 to 127 records.
Is it possible to create a dummy record that handles the repeating records correct?