Changing the Input back for cable box - automatically

Hmm. My cable box to TV is on HDMI 3.  I added a DVD player and when I turn on the DVD player, the input changes automatically to HDMI 4.  Then, I dropped my ROKU remote, set to HDMI 2, and when I touched the home button, the TV automatically went to HDMI 2.

Very handy. Now, when I want to go back to cable viewing, I have to change to TV mode, change the input back to HDMI 3, change the remote back to cable and then watch.

Is there a trick, or shortcut that makes it as easy to go BACK to the cable box input as it was to leave it for ROKU or the DVD player? Perhaps, program the auxilliary button to HDMI3, but no other action? Then, to return to cable after ROKU, I hit AUX, then Cable and I am back where I want to be?  Yes, it is a bit lazy, but I often overshoot when changing the HDMI input, making it take even longer.