Yes, it is possible
In the mapping, set the occurrence of the target to 0..unbounded
And in the mapping definition, the root to something like this:
The constant is the counter limit. (for instance 300)
When record 300 is reach, one message is created, so, 1 file with 300 records is created also
If you have 900 records, you will have 3 files
Hope it helps
Regards javi