RCA splitter?

[rlcal]

My problem is that I can't find a cable that will let me add two input devices to the amp in work. Basically I want to use this https://www.amazon.co.uk/dp/B015PZ7QO2/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=6SFHTCCWVAMK&coliid=I3V5FGUQN2K8B6&psc=1   I want to plug both the radio and this into the same input in the AMP so that I don't have to flip the switch on the back of the AMP which is on the top shelf about 12' in the air so requires a stool and is a hassle, I can just have the radio turned off and something plugged into the jack or nothing plugged into the jack and the radio on.

Is what I want a thing or is there another solution? 

[Guest]

Why does the radio need to be connected to the amp? What purpose does the amp serve?

[rlcal]

It's a standardised company wide set up, No idea why they thought it was necessary (could have something to do with it not being a normal radio, it looks like something that goes into a rack) nor am I allowed to remove anything from the current setup.