How to create an email alias that anonymously resends received emails to a set of people

Question

I have a client and plenty of vendors
I need my vendors to ask anonymously the client The idea is:
There is an email alias
There is a list of approved email addresses
If sender from the list sends to alias, the email gets resend with the alias as sender
Everyone receives that email with anonymity of the sender

My question is: Is there a tool / service that we can buy, or do I have to write the code and add it to our mailserver?

Answer 1

I don't know of a turn-key tool/service that can do this. But, this would be fairly simply to cook up by configuring your mail server to forward incoming messages to a short script that would perform the function that you describe. See What is the best way to redirect email to a Python script? for how this would work.