jane,
it depending on how much u wana follow the custom, but if really clashes, u can arrange like kyra. just make sure that person leave or hidden when groom n bride arrives will do.
like my case, i've yet to check with every1 involved but my MIL tells mi if really clashes then juz get them to stay in the room 1st when we arrive. we step into the hse liao then they come out (esp the elders, coz tea session mah)
but for ppl like sisters/brothers n MUA, if possible den change lor. for sisters, i'm trying to get all the singles coz they say married 1 cannot...