Business rules can only trigger upon a certain operation (e.g. After adding a member to a group). If that is what you need, it can be done using two business rules triggering Before adding a member to a group and After adding a member to a group. However, the conditions in your request are mutually exclusive. It is possible to cancel the operation if member of group A is being added to group B, but that is not something that can work along with removing a member from group A after adding them to group B. Could you, please, clarify that point? Live examples of the entire workflow will be much appreciated.