Interesting question. The law states that a person can become a caregiver and legally grow for a patient in RI as long as they live in the state and are over 18 etc. etc.. In order to prove residency one must just have a RI mailing address. So this person could technically live in both states and have a legal grow going on in RI while still living most of the time in Mass. This person could not legally grow for you in Mass. and be personally protected by RI law if the Mass cops raided the grow space. In regards to you, it is not illegal for you to posses up to your legal limit regardless of the source of the medicine. As you can tell there is a lot going on in this situation you described. You can sign up to have two caregivers which maybe worth your while in my opinion. Feel free to contact me if you have any more question, I am a patient as well as a caregiver.