L2TP/IPsec - more pre-shared keys?

Hi,
is possible to set more than one pre-shared key for L2TP/IPsec VPN?

I have one central VPN router at our company. I have about 200 VPNs users. I want, if is possible, have pre-shared key for some group of users.

For example:
our employees
external supplier 1
external supplier 2
etc.

Is possible to set another key for each “group”? Because, if I cancel contract with supplier 2…I will not change pre-shared key at all clients…

Thank you,
TwadaCZ

It is possible only if source address of connection is known. But you can remove L2TP usernames for that group of users.