Multiple ISAbs via TN

I am sure this is something very simple but my brain is not working.
I receive an EDI document with multiple ISA’s via TN, how can I process this document with multiple ISA’s as one and create one FF?
How would the TN rule be defined (what document type should be used coming out of EDI module) to trigger my process.
Thanx

~tS

what is the splitOption variable under EDITPA?

ramesh.