I'm testing a security setup to lock down access to some external facing servers by setting up a gateway server. This means everyone will now have to ssh to the gateway server before sshing to an external server.
So far the setup has users logging onto the gateway server as a communal (admin) user using their own ssh-key and passwords disabled. Then sshing to an external server as this communal user.
What I'm looking for is a way to automate the initial ssh hop so a user can type
ssh <external server> and the first ssh is setup for them in some fashion (ssh tunnel/bash alias?).
What would be the best method, if it's even possible, to achieve this?