I think I am just hung up on lacing at this point but what I am attempting to accomplish is to gather all conduit elements using the mark parameter. I am filtering marks that start with 20 and then finding all unique marks. My next goal is to gather all elements of each unique mark and then (eventually) combine the lengths for a total run length. I am simply having issues getting a nested list of each group of marks. Anyone know where to go from here? Thanks in advance!