Tom in the Eircom Phone book There are just 5 Brien Families And one Rock

Not sure if this helps

O'Brien Charlie

Round Tower Castle St Roscommon
 
(090)6626252 
O'Brien Elizabeth

Goff St Co. Roscommon
 
(090)6628611 
O'Brien Thomas

12 Abbey st Roscommon
 
(090)6625005 
O'Briens Health Foodstore

Lanesborough St Co. Roscommon
 
(090)6634174 
Thomas O Brien

Roscommon Town Co. Roscommon
 
(090)6637656

Ballyfeeney Rock

Kilglass Strokestown Co. Roscommon
 
(071)9633222