How to restrict the Initiative to ONLY its supplier contact selected at Initiative?

Summary:

How to restrict the Initiative to ONLY its supplier contact selected at Initiative?

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How can we restrict access to an Initiative so that only the specific supplier contact selected for that Initiative can view and respond to the Questionnaire? Currently, all contacts associated with the supplier can access the Initiative through the supplier portal, which should NOT be the case as we are providing a specific supplier at the Initiative.

Regards,

Abhinav..

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