newby to ERL, create a tunnel with split tunnel

I have a Office here in WA and one in BC, Canada, I have Comcast here and Telus in Canada, have a static IP at both offices offered by the respective modems in each office in bridge mode.

I bought two ERL's hoping to create a bridge and have all the traffic from BC go here in WA, and have all the public IP traffic use my Comcast IP for geo considerate purposes.

I don't see any clear how to - or is this not a doable thing on ERL

Thanks any and all for chiming in