Just getting back to you now.
If the s'names are the same they may be related to the person on the 'a'
part or first name on the plot.Highly suspect a mother and son or two
brothers and the mother.
Tradition was the original holding was divided between the sons, when the
man died, with the widow holding the part of it for her life.
What townland/ Barony-and OS Ref number?
If it was in six counties a letter to proni with an international reply
voucher would verify if they would send you the two pages of cancelled book
and what they would charge.
I Cannot point you in the direction of townlands in the 26 counties but
Barry could maybe answer that question.
If I can help in any way I will willingly do so.