If the two companies, are located in 2 close racks, why don't you buy a L3 switch and then you inter-vlan routing?
Let's say that you want to stick to your option with 2 x RV042 routers. If I remember correctly each of these RV042 routers have 2 WAN interfaces. One of the WAN interface of each you connected to the DSL line ( I understand each company has it's own DSL service). Then you build a VPN tunnel between the two RV042 and add route on each router so that the other company network is reachable through VPN tunnel.
Something like:
LAN-C1 --------- RV042-C1--------DSL --------INTERNET------------DSL---------RV042-C2--------LAN-C2
| |
---------------------------------- VPN --------------------------------------
This is not the best solution as all packets from one company to the other and viceversa will have to travel over VPN / Internet adding latency and bandwith limitation.
The second option would be to let the above design, but instead of creating a VPN tunnel, you connect together the RV042-C1 with RV042-C2 through the secondary WAN port (like back-to-back with a crossover ethernet cable). You configure a point to point network between routers and then route the LAN-C1 and LAN-C2 for reachability through the router's point-to-point connection.
If it's possible with this solution you eliminate the latency and bandwidth limitation.
Let me know if this solutions work for you!
Cheers,
Calin
