Interesting that the version "Na Conaraigh na sár-fir" specifically mentions TWO brothers. This is substantiated in official records at the time naming them as John and Pat Connery:

"Geallaimse gan bhréig díbh ní raghad ag insint éithigh
Ná faighinn a neart ná a dtréineacht in aon BHEIRT DEARTHÁIR".

BUt "A Choimín mahallaithe... " version has three brothers. And Storyteller says the name of the third brother was Séamus. Is there a reliable source for this? NOt a matter of the greatest importance - but I would be inclined to go along with the official record especially when backed up by a comtemporary poem.
Com Seangan