Include Objects with Missing Properties in Views with more than 2 Grouping Levels

Hello All,

I have a view with two grouping levels, the first level determined by property X and the second with property Y. I've set both grouping levels to include those objects with empty properties by enabling "Show objects on this level". I've deduced that an object will only appear in the view when the object has BOTH properties if property X is filled in (if property X is empty the object will appear in property X's level). If an object has property X but is missing property Y, then the object never appears in the view. I understand that M-Files searches with condition "Property Y is empty" never picks up those objects where "Property Y is missing", which probably explains this behavior. 

Does anyone have any clever workarounds to make those objects with a missing property Y but a filled-in property X to appear in property Y's grouping level, in the same way as if property Y was empty?

Thanks in advance for any suggestions!