Mark,
There is a number of ways to achieve this. You could 1) Use groups in 1 reference query to group Quotes under a specific "category" , 2) You could have 1 reference query per category (use filter or rules to INSERT / REMOVE depending on category) , 3).... (probably other ways to do it).
PS: You ask about queries in a form, this is a reference query (if you don´t know this yet) and to set it up you configure a relationship between Client and Quote and then on the Quote attribute on the Client BO set up the query.
