Please look at the attached file.
The yellow columns are group1, column G to N are group 2.
Group 1 has 3 pairs of normal and tumor.
Group 2 has 4 pairs of normal and tumor.
Now I add one more column "MTACH" to see whether Group 2 contains pairs in group 1. For example, row 2 in group 1 has pairs A1,A2,A3, group 2 contains A1,A2 and A3. Thus " MATCH" is 3.
Thanks for the formula.