sending custom values to connect compatible middleware?

I have an express server and I'm trying to write some middleware that checks to see if a user is of the specified level, but am at a loss on how to pass a level value to the middleware.

example app.js:

app.get('/restricted',verify.auth('4') , routes.index);

example auth.js

exports.verify = function(req, res, next, requiredLevel) {
    if(userLevel>=requiredLevel){next};
}

try this

verify.auth=function(requiredLevel){
 return function(req,res,next){
  // requiredLevel is visible here ..
  // manipulate req,res
   //..
  // call next middleware
  next();
 }
}

also working with sessions so you don't leave the user level to be specified by user..