Its a little convoluted, but yes its possible. Basically the customer would need to connect the netbotz dry contact cable (nbes0304) from the 450/550 netbot in room 2 to the output relay ports on the 450/550 in room 1. Then configure the door threshold to trigger a state change on the output relay. The dry contact threshold on the netbot in room 2 would then need to be configured to trigger the beacon alert action when there was a state change.
So door opens-->triggers output relay to change state-->dry contact sees this state change-->triggers beacon.
Be aware that if power is cycled on a netbot 200/450/550, the relay contacts change state as part of its start up diagnostics. Also the maximum supported distance of the netbotz dry contact cable is 100 ft using cat5 extensions.