The easiest way is to use the OBiTalk network to route the calls. I never used Trusted Callers, I just code the modifications myself.
This will work when the OBi100 and OBi200 are on 2 different account dashboards.
You said the Belize ISP is blocking GV. Anyway, assuming GV is working on SP1, use OBi Expert to make the following changes.
OBi200
Voice Services -> SP1 Service -> X_InboundCallRoute:
ph,pp(200222222)
Voice Services -> OBiTalk Service -> InboundCallRoute:
{200222222:sp1},{ph}
Replace 200222222 with the OBi number of the OBi100
OBi100
Physical Interfaces -> Phone Port -> OutboundCallRoute:
The 1st rule is: {([1-9]x?*(Mpli)):pp}
Change it to: {(<510111111*>(1xxxxxxxxxx|<1>[2-9]xxxxxxxxx)):pp}
Replace 510111111 with OBi number of the OBi200
Voice Services -> OBiTalk Service -> InboundCallRoute: ph
10 or 11 digit numbers dialed on the OBi100 will be routed out SP1 on the OBi200.
Inbound OBi200 SP1 calls will be routed to the phone port on the OBi100 and OBi200.