threaded comments

i am developing a comment/discussion board and i want to display the results in a threaded style. so far i have it all working except this one issue: each row has an ID and a parentid, say i have 5 rows: id : 10 most oranges come from florida id : 16 ---- Re: most oranges come from florida (parentid 10) id : 22 --------- Re: most oranges come from florida (parentid 16) id : 24 --------- Re: most oranges come from florida (parentid 22) id : 28 ---- Re: most oranges come from florida (parentid 16) i want the rows to know the id directly above itself so for example, row 5 (id 28) will some how know its parentid (16) is not directly above it and is not accociated with the result its above (24) i want to 'highlight' a row when the parent it belongs to is directly above and do nothing if its not. does this make any sense? very confusing nonetheless. hope someone understands.