DAHILL of Boston

I am looking for connections to these DAHILL siblings.
Mary DAHILL born in Ballyduff, Waterford County Ireland and immigrated to Boston, MA. She married Patrick CUSHING in Boston and had at least one son Richard J. CUSHING (Cardinal Cushing) b. 1895

Margaret DAHILL born March 23, 1866 in Ballyduff, Waterford County, Ire. and immigrated to Boston in the 1880's. She married Denis KENNEALLY in Boston.

Thomas DAHILL born August 14, 1868. He also immigrated to Boston in the 1880's.

I believe their parents were John DAHILL and Margaret HAYES.

I am looking for either ancestors or descendents of above.

Thank you.