Migration item to less items

[Ranakastrasz]

I need a migration script that takes every inventory in the game and replaces each 10 items of a type with 1 of another. Ideally, I would want to effect things on belts as well, but that seems infeasible.

[bobingabout]

As far as I know, migration will be a 1:1 replacement, and there's no way to set it otherwise.