I am sure you are correct that I am probably over thinking things as I tend to do that, but I dont see how what you are doing will work for me. You are taking two parameters from each item and comparing them to the other parameter in the same item. That is not what I am trying to do. I need to take first parameter of the first item and check to see which of all the other items it equals their first parameter. Using your example it would have to compare the 100 to the 300 to the 250 to the 405 to the 810 to the 520 and then do the same for the other parameter then, only if both of the parameters are equal create a separate sublist or group of some kind. Does that make sense? .In the list you have there, there would be no equal items, and everything would have to be in separate groups.I need to figure out a way to do like a custom sort, like how excel does, except in dynamo. I had the idea from yours that I might want to concatenate the two parameters from the same element into a single string, and then compare that to the rest of the items in the list. but when I tried to concatenate in dynamo, it doesnt actually do it. What am I doing wrong? shouldnt it be concatenating the 1.6914… with the 10 from the next list and so on? Why isnt it doing that? Even when I try to do it with “hello” and “world” it cant seem to do it. Why? Please advise. Thanks!