Block search on Chrome address bar

Hi all, 

I want to do a Web filtering with these rules: 

1) block ALL web browsing access except for a group of sities 

2) permit use of skype 

I complete these aims with "web filter" and "application control", so only certain sities are reachable and skype is usable. 

But I have the problem that if I insert a word on chorme address bar, it start with search. 

I want block also this behavior. I try to filter destination address to google sites with web filtering, but I had no success. 

I think that google use HSTS for this action and I don't know how to block it. 

Any suggestion ?

Thank you.