I am not a regular session player, although I have been to one or two. As it is not a regular established session, could Liam suggest maybe a handful of tunes, or pairs or tunes that could be included within the session? Including the key and even suggestions as to the version, (a link to the notes and/or sound file would be fantastic!)It would mean that those who do not know many or even, any, tunes, could learn them before and join in with a few, at least. I accept that this is maybe not the norm, but, I think it would involve more people and add to the session.
It is just a suggestion...