The only way I know of to do that is to apply the first two middlewares directly to your router with no path prefix:
router.use(middleware1, middleware2);
Then, in each of those middlewares, check the path of the URL and if it is the special path that you want to skip those middlewares for, then just call next()
.
if (req.path.indexOf("/somepath") === 0) { return next() };
Then, you can register your third middleware only for the path you are interested in:
router.use("/somepath", middleware3);
The first two middewares will skip the ones you want them to skip and the third one will only get called for your specific route.