Hi Ura,
yes, your 1 request can contain multiple "parameters" - in other words it can contain a group, a queue, a bunch of other fields, whatever you want. Think of them like parameters to a procedure - you can pass as many as you like, you aren't limited to only one "kind".
Same for return values. Unlike a Clarion procedure, which can only return one thing a NetWebMethod can return any number of things - variables, groups, queues, whatever.
Cheers
Bruce