Condition XPath Expression in SoapUI - I need to compare two values stored in custom properties

I have successfully captured four values from a response. I need to check that none of them are the same as any other (without worrying about every combination). In theory, checking that Value1 <> Value2, Value2 <> Value3, Value3<> Value4 are all true. I could go with a mathematical identity approach (eg where Value1/Value2*Value2/Value3*Value3/Value4 = 0).
I am failing in what I actually put in the body of the Condition XPath Expression in SoapUI (and the help is woeful, as always). Pretty sure I don't need to worry about the namespace stuff.
Right now I have three separate conditions eg ${#TestCase#Value1} <> ${#TestCase#Value2} but I am getting a "no condition is true for current response" message when I know that 3 of the four are true.
Also, if the condition I am looking for is true, I need to halt, or pop to a step that does nothing. Any ideas on that?
Finally, if anyone has tips for decent documentation for SoapUI beyond the woeful stuff they supply, please LMK.
Thanks in advance