Multi Inventory organizations under one operating unit

Hi -

Suppose the that we have TWO child inventory organizations A , B under the same operating unit X

* Is it possible to restrict order management  users to deal with just one inventory organization while [ creating orders , picking , shipping ,...etc ] ?

* and what about Receivable users ? can we control invoicing for just one inventory organization or certain transaction types ?

we don't want to create two separate operating units due to inter org transfer costing issues .

Please state your recommendations  , and helpful answers will be considered .

Best Regards