Need to restrict an iRule from passing external traffic, only internal.

Maybe something like this:

when HTTP_REQUEST {
    if { [HTTP::uri] starts_with "/subfolder" && [IP::addr [IP::client_addr] equals 10.0.0.0/8] } {
         the node command directs the request to the server 
         whether or not it is behind the BigIP. Make sure the BigIP 
         has a route to that server. 
        node 10.10.3.111
    }
}