-How to do Mapping ?

Hi, I'm currently developing clubs and groups...the individual group pages are displayed based on the group id like login.php?id=1...etc,during Creation of the group the user is allowed to enter their subdomain and to select a domain from the available list and all this details are stored in mysql database. The main requirement is that whenever the user types domain.subdomain.com they must be able to go to the home page of the group which will be in a separate server...i.e it must be able to map it to the page login.php?id="required Id" for the particular group... How can this be done....is there any way to do this in PHP... I still have a doubt whether its related to PHP :-) Thanks in advance Param