Alexander, thanx again for your help. <dtml-var "PARENTS[0][PARENTS[0].id +'_' + PARENTS[1].id + '_p1']"> is the right idea, but for some reason it's just quoting the HTML....I must admit I'm curious to know why the "PARENTS[0]" is used twice. <dtml-var "PARENTS[0].id +'_' + PARENTS[1].id + '_p1'"> seemed to make more sense to me, but it just returned the string that needed to be replaced. I'd also managed to get the same result (sting, no substitution) with <dtml-with id> <dtml-var "id+'_'"><dtml-var "PARENTS[1].id+'_p1'"> </dtml-with> Although I have no idea what difference the "id" in the <dtml-with id> makes. Thanx again, Chris