Redirect External Links!!!

I want to know if there's a way to redirect an external link (any link outside of forum domain) to a page on the forum. For example: if someone clicked a link on the portal it would redirect them to the login page.

On my portal, if you aren't logged in I have an Instagram widget displayed, and when you click on one of the pictures it takes you off site. I want to redirect that to the login page.

Thanks!
-Kynamic

Well if it is a code to Instagram then you really can not redirect to your forum's log in page. What you can do is create a widget only visible to guest that has the same information, but have the link that redirects to your log in page. Then when they log in they can see the widget that redirects to Instagram.