Machine user with same email?

I have a couple of servers for which I would like to configure SSH access to my private repos. It turns out one deploy key can only be used for a single repo, and the docs suggest a better approach is to create a “machine user” Github account for the server.

However, if I try to create a machine user account for each server, I need to specify a different email address for each!! I cannot use my same email address.

This seems like a terrible way of doing this.

So how should I configure SSH access from the servers to my private repos?