Queuing the HTTP requests from multiple clients

A Meteor Web App makes available data collected from 3rd party web sites available to the users. Now in the dev. stage and one user is testing, all is sweet. But when there are 200+ users and the Meteor HTTP package is getting all those requests from the users. Does it queue the calls to the 3rd party site(s) or does it make simultaneous POST/GET requests?

If it queues the http requests? What can I do so that the delay from such queue is minimized?