One feature I often find myself wanting is an ability to set an arbitrary consumption of a resource in a production line.

For example, say I have a line that is outputting 120 wire/minute. At some point I decide to divert 60 of that output to another factory, using it in another production line. It would be nice to have a way to indicate that 60 of that wire has been "used" and the other 60 is still "available". This would be especially nice for red outputs, which are the most likely to be repurposed like this.

In an ideal world I think the way this would work is a field below the "quantity" field that says something like "consumption", and putting a number there would reduce the displayed output of the line by that amount.