this happens a lot with subcools gear from what i've read.. and i've seen my one friend on here have twins ages ago.. i wouln't try and separate them though, not a very good idea, as i'm sure one if not both would croak in the process..
i'd leave them be, more than likely one will out perform the other and one will just end up dying on its own in a few weeks, that is what happened to my friends twins..
but i have heard of people taking twins to harvest successfully ... g/l.....