po_headers_all join fa_mass_additions

I have tables:

rcv_transactions rt,
rcv_shipment_headers rsh,
rcv_shipment_lines rsl,
po_headers_all pha,
fa_mass_additions fma

Need to join between tables of po_headers_all and fa_mass_additions.

Currently identified joins are:

po_headers_all.vendor_id = fa_mass_additions.po_vendor_id
po_headers_all.segment1 = fa_mass_additions.po_number

But its not working where PO have multiple lines.