Ques regarding Sub Domain, Category and sub categories

Hi,
I was wondering how I can achieve this functionality

On the main page of my wordpres website (www.mysite.com) I wanted to show the latest blogs. All fine. But here I want to show on the right, only the main categories, lets say Mens, Womens, Children.

When someone clicks ‘Mens’ the user is taken to a sub domain called mens.mysite.com. But here I want to show sub categories based on the parent category (ie sub categories based on the category ‘Mens’)

I am using WP Subdaomins plugin.

Can this be done, if so how? Any help would highly appreciated.

Thanks
IT Guy