Table Relationships

I have a table named Projects.  There are two child tables named Options and PO's.  From the Add PO form I'd like to be able to "Add Options" to the options table by clicking on an "Add Option" button.  The trouble I'm having is that when I click "Add Option" from the Add PO form, the "Add Option" form doesn't relate (auto-populate) the Project that the PO is related to, the related project field is blank and I have to manually type it in.  I can't figure out how to relate the tables and fields so that the "Add Option" form knows which Project it's creating records for.

Any suggestions are appreciated.

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Aaron Lavender
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