You can create new menu items in admin panel>>pages&menus>>pages&menus .
Choose "External URL" when adding new page.
As URL use URL for the search results by tags. For example: http://yoursitename.com/...-tag?tag=TAGNAMEHERE

Yes, it works, but in the other menu i wanted other blogs difrent then TAGNAME, so i dont repeat info.

Bhavika, manually editing all blogs and giving certain tags only to needed blogs might work for you.

Also, just a suggestion, you might want to hide "tags" field from "post/edit" blogs pages. So that only you as admin can add tags in database.

How can i ido that? hide the tags

This can be done as a custom code modification only. 

Do u Know if anything like this was done before?

Bhavika, not that I am aware of.

Thread revival :)

With so many devs now building categories into main feature plugins - Groups and Blogs plugins look and use a bit basic.

It would seem to my users, and to me - that site wide categories would prove a very good idea indeed.

Matt

You can vote for the new feature ( adding categories to blogs) here: http://oxwall.uservoice.com/...es-for-the-blog-page