Redirect url by subfolder

That can be done in several ways. By a "set of servers", I assume you are referring to a "pool" in BIG-IP terminology. If this is the case, a simple iRule that inspects the URI can change the pool the connection is going to. Something like this:

 when HTTP_REQUEST { 
   switch -glob [string tolower [HTTP::uri]] { 
     "/content*" { 
       pool pool_1 
     } 
     "/othercontent*" { 
       pool pool_2 
     } 
     default { 
       pool pool_default 
     } 
   } 
 }

This way any request to "/content*" will get routed to pool "pool_1", requests to "/othercontent*" will go to pool "pool_2" and everything else will go to pool "pool_default".

The switch "-glob" allows for wildcard substitutions so you can do exact matches or wildcard matches as I did with the asterisks.

Hope this helps...

-Joe