Well, you could learn about vectors here:
http://www.geocities.com/SiliconValley/2151/math3d.html
If I understand you correctly, though, I don't think vectors is what you're looking for. What you could do is just use an array to store the numbers of the matrices in sequential order. For example, assuming your player was at matrix 6, you would get:
dim matrixNo(9, 9)
matrixNo(6, 1) = 8
matrixNo(6, 2) = 9
matrixNo(6, 3) = 7
matrixNo(6, 4) = 5
matrixNo(6, 5) = 6
matrixNo(6, 6) = 4
matrixNo(6, 7) = 2
matrixNo(6, 8) = 3
matrixNo(6, 9) = 1
Of course, that would be a rather dull and monotonous way to do it. You could probably do it with a couple of FOR NEXT loops, though.