Bring selected category/brand in top 3 auto suggestion

Hi All,

In our project there is is a requirement that, if some text is typed in the text box, then accordingly top 3 categories/brands will appear in the auto suggestion section, and these top 3 category/brands should be configurable. The requirement is as :

Customer types 'shoes' in the text box, then in the auto suggestion section, it will offer top 3 configured category/brand first and then the relevant products:

e.g: NIKE SHOES(category1) PUMA SHOES(category2) ADIDAS SHOES(category3) Product1 Product2 Product3

and where and how we can configure these 3 category/brand which we want to show on top, so that if in future we can to promote different brands then we can easily manage them.

can some one tell me that how I can achieve this. Please reply on this query.

Thanks in advance.