[AccessD] Move children from one parent to another

I have been asked to add a feature to an existing app and am trying to think
of a cool way to do it. The general idea is this:

There are Factories.(PK FactoryID)
The Factories contain Machines (PK MachineID, FK FactoryID)

On occasion, the client wants to move one or more machines to another
factory. Obviously the back-end stuff is simple: for each machine selected,
change the old FK to the new FK.

My initial thought was a dialog that lists the machines in the currently
selected factory, allowing multiple-select; plus a list or combo that lists
the other factories owned by the client. Grab the PK of the new Factory and
walk through the selected Machines, changing the FK to match.

Anybody got a slicker idea?

TIA,
Arthur