Sister trouble

Both Stephanie and Emily are having a rough week as sisters. Stephanie has begun to bite Emily and Emily has 3 places right now that have bite marks on them. Emily though has begun to push Stephanie away from her as soon as she comes close. Sometimes, after Stephanie bites Emily and she needs to go and apologize, Emily doesn't want her coming close. It's been very hard because part of the problem is that we don't think Stephanie understands that what she is doing is wrong and is hurting someone, and the punishment she receives is related in any way to what she did. We need to find a different way to reach her but we haven't figured that out yet. Those 2 girls are really testing our patience.