Complicated VPN

Hello.

I am trying to make a very complicated VPN connection. I will try to explain as best possible.

CompanyA (from here on CA) need a VPN connection to CompanyB (from here on CB).

CA already have VPN to link several different locations together. 2 of these locations needs to be able to use the VPN connection to CB.
Info about locations:
Location 1: has RED10 appliance.
Location 2: has ASG120 appliance.
Both these have a VPN connection to Location 3 which is also a ASG120 appliance.

From Location 3 there is a VPN to CB. Tunnel is up.
CB have 3 internal networks which CA needs to be able to interact with. When they do contact the internal networks of CB, they need to come from 1 specific network, which differs from their normal internal networks. This is made with SNAT on Location 3.

At Location 2 there are static routes, that routes every package going to one of CBs internal networks, through the ASG120 at Location 3.
Location 1 has no possible way to configure this, so I am thinking they might need an ASG there aswell.

I can not make this function. Can anyone tell me if they spot something here that is completely wrong.

Best Regards
Marcel Jensen
VestNet