A hand written letter? Im not sure about that. I know あなた can Eメール jon but lately they havent been able to interact with their ファン (or so ive heard). If i come across anything i will post it here.
Probably...maybe write it to one and in bold on the 上, ページのトップへ of the letter write:Read to the entire band please. Then somewhere in there ask if there's a way あなた could write to them as a band
