The FF-SHOP does not assign Group IDs. Only Issuers generate Group IDs in FF-SHOPs. Issuer assigned Group ID is an optional element for a group's initial premium payment. For the initial payment, the FF-SHOP will use the Payment Transaction ID (also sent on the Group XML file and 834 enrollment transaction) in HIX 820 transactions. The Payment Transaction ID is what connects the HIX 820 and the Group XML and 834 enrollment transaction. If the Issuer-assigned Group ID is known, then the FF-SHOP will transmit the Group ID with the Payment Transaction ID on the HIX 820.