You cannot email a supplier you cannot name.
So your supplier names them for you. The invitation goes out in your supplier's name, not in yours, and the new company answers exactly the way the first one did: one screen, no account.


The request comes from someone they already work with
A spinning mill ignores an email from a brand three steps downstream. It does not ignore its own customer.
Nothing about anyone else's chain
A supplier sees their own request and a preview of what the brand will see. Their sources are never exposed to your other suppliers.
Nothing, and no account
No licence, no password, nothing to install. One screen, one request at a time.