How to Split Regions Is there any way I can split a region into 2 different regions. For example, in Garland theme I want to split the HIGHLIGHT block region horizontally into two regions.. 
is it possible ?

Any help would be so much appreciate.
You should build your own theme and edit the tpl file to apply the layout you need

the easiest way is to build child theme and edit what you need in tpl files 

create child theme