Pass AutoNumber to next form...

Hi, I am having difficulty sending the autonumber to a number field in another form... Seems simple enough, but this is how it appears in my app

2 Forms

2 Tables

Main Form

Main Form Table

------- Subform

------- Subform Table

Main Form - Generates Autonumber.

I want Subform AND all other subforms to inherit this unique number on multiple records in the SubForm table.

Please help me.

Thanks