Using Two Domains in Waterfall for 'Find Work Email' Functionality

Hi Clay, when I use the waterfall 'find work email'. I want to know if you can run a waterfall with 2 different domain as input. For example, I want the waterfall first to run on domain 1, with no results I want the waterfall to run and try domain 2. To maximise the results. Is that possible? Or do I need make 2 'find work email' waterfalls, to give 2 different domain inputs. The downside of that is using many columns. Looking forward hearing from you.