right click menu - select search
It's not possible in Safari. It uses whichever search engine you define in Safari preferences. And the same applies to Google. Best I can do is use the one option they offer. I  don't know about other browsers.  There might be a programmatic way to do it but I don't know how to do it. 

In Safari, it's way easier to change search engine. Go to address bar  (command+L), enter space(spacebar), choose search engine. There's no need to go to Safari preferences to do it.