What about interest on the loan? Are you paying that or your parents? If it's them, it'll add up to quite a bit over the years. Of course, they wouldn't have had to get it if they hadn't given some to the others, so the cause is shared, but it's mainly incurred by you, if we're getting down to the nitty-gritty.
I'm paying the interest on the loan. Ie. I'm paying the interest instead of paying rent to a private landlord