Advice appreciated - Multiple relays activated from one pin

Hi All

I have been asked to build a car audio display wall and i have a question.
I only need to switch the stereo audio signals not the power of the units. So i plan to use a 4 relay board for each head unit.
Can 1 pin from the Arduino activate the 4 relays on the board simultaneously so the L+- and R+- of the head unit switch on and off.

i plan to have ten relay boards and use a touch screen interface to be able to select the audio output from the selected head unit and route to the speakers.

Any advice would be appreciated.

(deleted)

Ah yes, that makes sense, thanks.