Distribution Set - can it be edited in the AP invoice transaction

Summary

Can a Distribution Set be edited for one parameter?

Content

We have a couple of AP suppliers who only supply language translation services. 

I want this expense to go to the same Distribution Code every time, with every invoice, for each of these suppliers.

I know we can set up a Distribution Set.  But can we:

1. assign it to populate automatically for a specific supplier?  Or will it have to be selected every time?

2. edit the combination when the AP transaction is being created to modify one parameter of the code, in order to assign the expense to a new client every time (the Client code being a part of the Distribution string)?