I have the standard type category structure but one category I would like to not have any items within it and when the Cat title is clicked instead of opening the category it works as a link to another website?

You can use an extrafield in order to display that link.
You can render a specific extralink based on its alias, github.com/kricore/Advanced-templating-with-K2/blob/master/_inc/cheatsheet.php#L168-L173