IP.Nexus allows account holders to create alternate contacts who can submit support requests on your behalf.
On my account I have a package called "Basic Widget". I can create an alternate contact assigned to this package, and we will then both be able to submit support requests related to it, and view requests each other have submitted.
This is the alternate contacts page:
You can add a contact by pressing the button at the bottom, which will allow you to select which packages to assign them to.
And of course can remove contacts by pressing the button in the list:
When the alternate contact logs in and visits their client area, they will see, and can reply to, existing support requests, or create new requests associated with the package assigned to them:
When viewing a support request in the Admin CP, support staff can identify who is the main account holder, and who is the alternate contact: