loadbalancing on the 2 nd remote location of bridged link

a point to point link is working in AP Bridge WDS mode. The existing link is catering to carry internet from one location to other. The ISP gives Internet connectivity at one location using ADSL bridge ( I do not have a possibility of giving a gateway on LAN side of ADSL device)

Need to add one more remote location where similar internet connectiity is available.

I made AP WDS network between the three. However I am unable to achieve loadbalancing and fail over. ie from the central location which is the client’s office , i need to give high availability internet access by configuring FAILOVER and Load balancing,

As per my understanding FAILOVER and LOAD BALANCING Is possible only if routing is done between my central location and 2 remote locations.

Howeer if i do the routing in the above scenario the trace would not go beyond the ethernet port of my remote radio, since i am unable to give the gateway on ADSL bridge.

is there any way out?