Complex sentence: Similarly, a business may "invite" a customer or partner organization to be part of their Addressbook (and thus enable two way communications); the counterparty must "accept" such an invitation for the Addressbook entry to be established on both sides.
Split into simpler sentences: Similarly, a business may "invite" a customer or partner organization to be part of their Addressbook (and thus enable two way communications). The counterparty must "accept" such an invitation for the Addressbook entry to be established on both sides.