How do you limit Checkbox list row / columns

Hi there,

I was wondering if some one could help me. I am looking for a way of using a lookup wizard from a reference table as "Checkbox list" but limiting the number of row / columns of data. There was a previous post which was marked as solved but the solution did not work.
For example If I had check box list containing:
Cities

------

1. Amsterdam
   
2. Cairo
   
3. Hong Kong
   
4. London
   
5. New York
   
6. Sydney
   But wanted to display them as Layout 1:
   
7. Amsterdam___4. London
   
8. Cairo___5. New York
   
9. Hong Kong___6. Sydney
   Or layout 2 (if the checklist is horizontal):
   
10. Amsterdam__ 2. Cairo_____3. Hong Kong
    
11. London__5. New York__6. Sydney
    How would I do this?
    
    Many thanks in advance to anyone that helps.