I'm wondering if it is proper and a good idea to send seperate queries simultaniously to agents who work for the same agency. Is this something you recommend?
Simultaneously querying two agents at the same agency is a no no.
And some agencies say a no from one agent is a no from all of the agency's agents - so you can only query one agent from the agency per book.
But some agencies allow you to query a different agent at the agency after the first one has passed on it. So, you could conceivably work your way through the agency's agents, one at a time. Not a great approach, because if an agent thinks something has potential but isn't right for her, she might pass it on to a colleague. But some agencies are fine with your working your way through the agents, so long as you don't query more than one at any given time.
So, pay attention to submission guidelines and research the prospective agents carefully.
good luck.
~suki