I have multiple destination sets that depends on a rule that is based on a smart object's property. 

My problem is that sometimes the smart object's property returns a null value and I don't know how to determin if my first variable is null in the destination set rule editor.

Is there a way to get to the code behind, or is there a way I can use the rule editor to determine if my first variable is null.  I tried SmartObject.Property = null, but that does not seem to work.

I was also under the impression that when you add multiple destination sets, there should be a checkbox saying first true or all true.  I do not get this, not sure if it should be there?

Any help would be appreciated.