I'm suggesting adding your new (unnamed) box in to the VPN network, and ONLY adding the peer-to-peer configurations. Select one to be passive.
e.g.: On the unnamed box:
Code:
ike esp from 1.8.38.x to 1.8.15.x
ike esp from 1.8.15.x to 1.8.38.x
and on VPN 2:
Code:
ike passive esp from 1.8.15.x to 1.8.38.x
ike passive esp from 1.8.38.x to 1.8.15.x
Nothing fancier. See if you can get SA and Flow established just like that. Worry about your 10.x.x.x networks later.