I think you have to adopt a professional attitude to this. You are an employee and must care for, impartially, all the residents in the home. That is your role. Whether you know them socially or not is really irrelevant. Nurses, doctors and other health care workers have to deal with people they know socially all the time. I'm sure you will soon get used to what must feel a strange situation at first but if you feel really uncomfortable about dealing with this the only thing you can do is look for a job in a different Care Home.