I want to create a tunnel-bridge within 2 GL-MT300N one located into my office, second into my house.
all outbound traffic from my house must be transit by tunnel and if I try to lookup my IP from house (eg. whatismyip.com ) this must be the same as I get at the office
If your office has IP address and it accept incoming traffic then this is possible. You can set up a vpn server or shadowsocks sever in one of the router and another use client.
We are developing this now and hope to make it work soon.