You don’t say what faith the family were. I suspect it was a mixed marriage and they married in the RC faith (because I cannot find any trace of the marriage in other denominations records.) If it was RC, St Johnstone falls within All Saints (Taughboyne) parish. Their baptism and marriage records start in 1843. So you may be able to find James & Susan’s marriage in 1852, though it may not necessarily record their parents names. At that time all that was required were details of the couple and their 2 witnesses. However perhaps the records may have more than that.Copies are held in PRONI, Belfast (MIC1D/85) and in the National Library in Dublin.