I have not found any connection to possible siblings at this point. I have old letters r/t a big estate from St Louis in 1939 that my Husband's grandfather was trying to find a connection to but with no luck. The lawyer's notes mentioned a Sarah Campbell that married a William Campbell from Derbrough and had atleast 12 children. This all had to do with brothers Hugh and Robert Campbell who immigrated to the US. Our William may have been distantly related but was from Gortin. I've seen notes connecting him to the McNickles and McFarlanes. I believe our William's father was likely named Robert, all were Church of Ireland.
Don't know if that helps. Carol