Icons for mine control towers

I´m planning for future playthroughs to keep my mine control towers built all in an array on one location. It would be perfect for better visibility to have the option to assign an icon from the available resources to each tower which is shown at the top (like the ones at the roof of the unit storages, but customisable).
Don´t know if this makes sense, I just started "digging" into this fantastic game, just scratched the surface ...