Read ingredients on an assembler…

I’m still running the base game. With that out of the way, let me explain the issue. I have a block of assemblers getting their recipe set from the circuit network. When I set one of them to read recipe ingredients, the ingredient signals just end up back on both red and green wire. This fouls up my circuit signals on tier 2 recipes like green circuits. The moment my read assembler goes to green circuits, the rest of the assemblers want to make copper wire.

Is there a way to cleanly separate the signals, without using a separate, idle assembler to get the ingredients from?