You cannot have multiple "operational contacts." The operational contact is only responsible for receiving the initial access codes to your company's Partner Workspace.
Upon their first login, the operational contact can add members directly from your company's Partner Workspace in the "Workspace Admins" module.
Please note, anyone added in "Workspace Admins" receives digital rights only, not physical ones. If you also want to invite your members to the physical VivaTech event, you must send them an invitation from the "VivaTech Invitations" module.