If there were girls interspersed among the 5 boys and they stayed and married in Ireland, you might find their marriages in the civil marriage index on the familysearch.org pilot site. Registration of non-Catholic marriages began in 1845 and there are two marriages of Barber brides in Monaghan in the index, one in 1846, the other 1848. You might get the registrations, determine the parishes, then hope they've been filmed by the LDS, as that could lead you to the boys' baptisms. Diane