Can someone help me out with a macro that will merge & center a number of
cells?

Data looks like this

Column A Column B
1. ABC Company Category 1
2. Category 2
3. Category 3
4. Category 4
5. Category 5
6. Category 6
7. XYZ Company Category 1

and so on and so forth. What I want to do is to have a macro merge & center
A1:A6, then move on to A7:A12.

Can someone help me out?
Thanks