The marriage certificate of Thomas and Matilda should list their fathers' names and occupation as well as the names of 2 witnesses who might be related.
IGI lists 4 children of Thomas and Matilda: John (1872), Matilda (1874), Robert (1879), Maria (1880).
Londonderry Sentinel, 26 Feb.1867: February 21, in the Ballyarnet Presbyterian Church, by the Rev. R. McCreery, Mr. Thomas Norry, Ballymagroarty, to Matilda, daughter of Mr. James McCorkell, Dundrain.
To find more details of parents and possible siblings you will need to search for church records.