Family History - where are all the names??

I spent last night scanning a few photos borrowed from my Aunt Jean. - One of my favourites is this one, I'm guessing is a family grouping of about 25 young people - taken in Auchencairn, Scotland.  My grandfather, Thomas John, is the young man in the middle row, dark jacket and heavy 'tash.  He emigrated to Australia in 1911, when he was 34 (I have a copy of his Passenger Contract Ticket  too) - my first guess was this was taken in 1911 or thereabouts, but the young man in the photo is certainly younger than that - could this be taken in 1900 - a celebration of the new year?  I'll have to research into the costumes a bit more....
By the look of the young man top right with another spectacular 'tash - this is a family grouping  -  I just wish there were some names on the back !!!!