Sullivan-Russell descendents

I have been trying to put together my family tree but having a double barrelled surname it has been very difficult.  So far I have been able to trace back to where a William Sullivan who was born in Killarney came to England with his wife Mary and their son Daniel and daughter Mary.  If the census is correct they had a further daughter Anna who was born in Wales whilst en route to London. Two more daughters Ellen and Julia were born in Limehouse, London.  Ellen married  James Russell in 1874 and it is believed that Ellen had an illegitimate son called William and to give William a legitimate name Ellen and James joined their surnames to give Sullivan-Russell.  My own father who was call William Sullivan-Russell passed away in 1985 and I am the only surviving male carrying the surname forward.  I have no sons neither does the son of my late brother.  I know that my father used to return to Killarney every year to see "Family" but I never knew this family.   My father and mother divorced in 1942.  I recently tried to find the name on Google and came across a lady called Anna O'Sullivan-Russell.   There is a photograph of her on the internet holding a child and appears to be accompanied by a male.   This may have been a christening and the male person could be Anna's husband.   This male could well be a relative of mine especially as he bears a marked resemblance to my late brother when he was about 35 years of age.  I have attempted to contact Anna via facebook but she does not respond, To my mind there is a very strong possibiility that the Sullivan-Russell family and the O'Sullivan-Russell family in Dublin are connected, The combination of the names Sullivan and Russell co-joining in two different countries is so remote I feel that we have to be connected in some way or other.This is where I need help from across the warer.  Is there anyone who can help me?

Regards

Brian Sullivan-Russell