Adding a second IPSec Tunnel to a different gateway

[cre8toruk]

Hi all,
like a lot of people at the moment we have a lot of people working from home and using our Ipsec VPN to RDP into their work PC's... bit mickey mouse but seems to work ok.
I've inherited two DSL connections of 70mbps / 20mbps but obviously our IPSEC VPN only uses the 1st DSL connection. It is set up to use RADIUS authentication.

I had a thought that I could create a second IPSEC tunnel utilising the second DSL connection but when I try I don't have the same option to use RADIUS authentication.

Can you advise if it should be possible to do what I'm looking to do and what the possible reason could be for why I can't see the radius authentication option I'm looking for?

thanks in advance,

Paul.