kind of store / batch query procedure

relating to my last post https://jira.mongodb.org/browse/SERVER-16735?filter=-2
concerning the no solutions to embed big size items array , and the non sens to post thousands of $in reference ,
i was thinking of an alternative solution, i guess its a common pb so..

If a kind of stored procedure was possible , it should solve this problematic, example:

I put my blacklist items in another collections, great,
now i want to make a 2 step query to retrieve my elements with blacklist id ref without posting tons of ref _id in the second query.

Its possible if i can call localy (avoid post size pb) a procedure / batch querys were the first result query stored in a temp variable, then perform the second query. example:

myprocedur(param,option){

//query1
$var = get all id ref in blacklist collection ;

//query2
get all id in profile collection $in ($var)
}

Sorry for the long post but i think its very important problematic, there is actually no other solution to my pb, and im sure im not alone..