One Way Only

A girl lives in a town where it is splitted into two groups, but she is not in any so is her brother, she has to do an Ept exam to see which one she is in, either Malonisum or hyprotin but the biggest rule is that when they are placed in a group they can not get to see their family again or else they will be killed, she failed to carry this out so what will she do to prevent everyone from trying to kill her and her family