Yes, you need to program what is called bank links. I forget the exact sequence but in the pull down menu there is a way to link various scan lists so they will scan. Icom does not call it scanning I believe they call it searching.
I believe when you get into the menu option for bank link you have to scroll through the active banks and select which ones you want to "scan". I no longer own the R20 so I am going from memory on this. Somewhere there was another form of an easy to use manual on line.
Go into "set mode" then expanded mode, then bank link then scroll down to select the banks by pressing the the 8 key to activate the bank. It can be found on page 58 of the manual.