Megamenu 1st level grouped with columns?

I've attached some photoshop work of what I'm trying to achieve. I can get the columns I'm looking for when not-grouped, but not on the first level when grouped? I do understand megamenu and accounting for padding/margins of the submenu width when doing this on other template club's templates. Is this possible with Gavicks'?

Hi

Our templates are using megamenu so all You know from other templates familiar with this extention is working here too. Please take a look at megamenu documentation: http://wiki.joomlart.com/wiki/JA_Templa ... Navigation