For both the Path or File value and the Process value in a rule, you can enter more than one string.
When you have entered the first Process for this rule, click the Expand button to the right of the box.
You can then add additional paths or files by typing them in the box and clicking Add after each one.
You can remove any file or path by selecting the file or path in the list below the Path or File box, and clicking the Remove button.
If you enter multiple paths or processes for a rule, the Custom rules page shows the first path and then (multiple) in the relevant column for this rule. Moving the mouse over the value shows a tooltip with the complete list of paths or processes for the rule.