To enable the supplier contacts of a parent company to respond to the negotiations of their subsidiaries, the parent supplier must be added to the negotiation as an invited supplier. This will allow the parent supplier contacts to access the negotiation through the Oracle Supplier Portal and submit responses on behalf of the subsidiary supplier. The parent supplier can also view and monitor the negotiation progress and status. The parent supplier must have an active supplier portal user account and the appropriate roles and privileges to participate in the negotiation.

References:

How You Invite Suppliers to Negotiations1

Oracle Supplier Negotiations2

Response to Negotiations3