They shouldn't split if they won't work correctly in two rules (at least that hasn't been what has happened in my case). I mean:
Hide field 1 if field 2 = "oranges" OR Hide field 1 if field 3 = "grapes" works just fine as separate rules doesn't it?
This:
If Field1 is equal to Variable or
If Field2 is equal to Variable2 or
If Field3 is equal to Variable3
Seems as if it could easily be 3 separate rules and still work correctly... But, as long as you have something that is working the way you need it to, problem solved. :)