Greetings. How does one differentiate whether "su" indicates possession by a third party (i.e. "his" or "hers), or whether it indicates possession of the person to whom the statement is directed (i.e. "your") in the absence of any context. Example: "Mi casa es su casa" Obviously, If I walked up to a friend and said this, the context would most likely indicate the meaning to be "My house is your house", but how does one know for sure? Thanks.