Advanced Query String Value

Does anyone have any experience with using "String Data" within advanced queries within JDE?  Looks like you can pass in specific information related to the User ID who is logged in.  My client would like to pass in the user's default BP so they can build more general queries that apply across multiple branch plants.  Example, instead of creating a new query for held orders in every branch then assigning those to a Role, they want to create one query which will use the default User BP that is signed in.  Any help would be appreciated. 

Thanks, Bryan