allow specific subnet to access single URL directory

I'd probably do something like this.. I haven't tested it but should give you some ideas

when HTTP_REQUEST { 
    set url "https://prodfmw-osb.bm.com.lb/cvs/chn.website.cvs.Account_1.0"
    if {[class match [IP::client_addr] equals "rackspace"] } {
        if { not [string tolower [HTTP::path]] equals $url} {
            drop
        }
    }
}