Multiple Pre-Shared Keys IPSec

[simonwait]

Hi

I have an L2TP setup with IPSec Preshared key which is working but now I would like to add someone who can connect into the VPN but ideally using a different Pre-Shared Key. The trouble is both the users on the original VPN and the new users are on mobile devices so I cant input a remote gateway IP.

Thanks in advance for the help