Hi,
I’m afraid this is not possible, as two separate search fields cannot be connected or triggered with a single button. You can for example enable the search button on one of the fields, and disable on the other one.
One possibility could be, to add a custom button via a page builder (maybe visual composer or something else), and the add a custom JS function to that button. The plugin has a javascript API, so it can be used to trigger both searches. If this code is exectued on button click, it would automatically trigger both searches:
ASP.api(7, 'searchFor');
ASP.api(8, 'searchFor');