In order to do that, you need a 16 line to 4 line encoder but Falstad doesn’t have one that I could find. You could build it out of logic gates, of course, but that would be tedious at best.

4] Logisim. Logisim is a portable logic gate simulator software for Windows 10. Hence, you need not install it on your PC. All the components required to build a circuit are available on the left ...