If you are not using a bitstring or custom for the PopulationType in your ga options, then you can encode this constraint using the nonlcon input. This would require you to write a function that returns C and Ceq such that C( x)<=0 and Ceq( x)=0. In your case, you can let C = [] and then assign Ceq to be a vector where Ceq(i) is 0 if individual i is fulfilling your constraint and 1 otherwise. You can use ismember to test if the x is a row of A.
If you are using those options for PopulationType, then ga and gamultiobj ignore all constraints. In this case, you may consider using gamultiobj and defining an objective function that penalizes the x's that are not a row of A. This would work in a similar way to how Ceq is formulated.
