Sending requests to specific URI to different pool based on load

I was going to try and use snmp to pull CPU utilization metrics and put the same nodes into separate.

 

 

node1,2 = live webservers

 

node 3 = maintenance page

 

Pool A includes node1,2 and node3 as failover

 

Pool B includes node1,2

 

irule with logic: URI startswith /start goto Pool A, else Pool B

 

 

If snmp threshold is tripped, PoolA fails over to node3. Would this work?