Which county should I support?

I was adopted from Ireland to the U.S. as an infant, but my Dad and his children/my siblings (who I’ve never met) live in Ireland. My dad played in county Roscommon growing up (never for the county team). My younger brothers currently play in county Leitrim (not for the county team). Can I support both counties? Do I only pick one of the 2? Or should I support a county that actually has a chance to win it all?