Varnish multiple backend configuration?

[Nathan McSween]

Would this work as a simple load balancer configuration?

backend apache {
            set backend.host = ""; set backend.port = "80";
        }

backend nginx {
            set backend.host = ""; set backend.port = "80";
        }

        sub vcl_recv {
            if (req.request != "GET" && req.request != "HEAD") {
                pipe;
            } if (req.http.Expect) {
                pipe;
            } if (req.http.Authenticate || req.http.Cookie) {
                pass;
            } lookup;
         }

         sub vcl_pipe {
             pipe;
         }

         sub vcl_pipe {
             pipe;
         }

         sub vcl_pass {
            pass;
         }

         sub vcl_hash {
            hash;
         }

         sub vcl_hit {
            if (!obj.cacheable) {
                pass;
            } deliver;
         }

         sub vcl_miss {
            if (req.url ~ "/.(php|py)$") {
                set req.backend = apache; fetch;
	    }
            else (req.url ~ "/.(*)$") {
                set req.backend = nginx; fetch;
	    }
	 }

         sub vcl_fetch {
             if (!obj.valid) {
                 error;
             } if (!obj.cacheable) {
                 pass;
             } if (resp.http.Set-Cookie) {
                 pass;
             } insert;
         }

         sub vcl_timeout {
             discard;
         }