Intercompany Eliminations - not at First Common Parent

The short answer is YES.  You can do this with rules, pretty easily.  In fact, you don't need to do the whole elimination calculation, you just need to tell the rules where to you want to see the elimination in the hierarchy.  Then add this line in your conditional statement...

api.ExecuteDefaultElimination()

Another option that is in some way less flexible, but uses no rules, is to make the parent entity isIC.  Then the eliminations will happen there and not at the first common parent.