I am from a very large family and have an adult sister with Downs syndrome who lives in NJ. Two of my other sisters currently have durable POA for financial affairs for the sister with Downs, but our family would now like to have me and two of my brothers who are closer in age to the sister with Downs become legal guardians for her. This was recommended to us by several of her doctors and her DDD case manager. If my two brothers and I became guardians for my sister, would this nullify the POA that the two other sister's currently hold? We would still like the sisters with POA to manage her day-to-day finances and have myself and my two brothers manage long-term finances (e.g., investments), living situation, etc. Is this possible?