Disable UPS (unified power supply)

I have a bunch of UPS-type cellphones, but when I activate them they draw power from the UPS my character is wearing. Does anyone know how to disable the phones drawing UPS power. Even if the UPS is sitting in my backpack it still works for some reason, does anyone know how to disable this? It seems as if there aren’t any threads about this, and as a C.R.I.T. Engineer main this is basically super duper important.

Unload the UPS or replace your Smartphone (UPS) with a normal Cellphone with 0 battery.
I am not very experience with UPS devices as I very seldom use a UPS once I get a recharging station set up outside my base though, so if there is a feature for that, I am unaware of it.