1. A method comprising the steps of: a) establishing a collaboration session between a first client and a second client through a session host server; b) retrieving a requested resource from a resource host server through the session host server in accordance with a first URL of a plurality of URL's from the first client; c) modifying the retrieved resource by modifying each URL of the plurality of URL's within the retrieved resource referring to the resource host server other than the session host server so as to redirect the request through the session host server; d) determining, by operation of the session host server, whether to cache the modified resource based upon needs of the collaboration session between the first and second client and if the modified resource includes at least one of a pre-determined filename extension, a specified resource expiration date, or a command containing a method other than GET; and e) providing the modified resource to the first client such that each modified URL designates operation through the session host server.