Nanny 911: Parenting and Disciplining Stepchildren
This is tricky as the rules may be different at their other home. I suggest sitting down the kids and making a set of family rules, work it out with them and make it fair! You can have them sign an agreement and if they break the rules agree on a consequence for it, once the rules are clear and the boundaries set life should get easier!
Get more child behavior tips from the Nanny 911 Nannies!