I can't think of how to do this in DNN, but you could use IIS URL Rewrite
Using URL Rewrite, you can define all sort of rules, via IIS, that will tell IIS when to Redirect a request. You can use Regular Expressions or Wildcards to define the rules, which get written into the web.config.
Something like:
Rule 1: Request to www.mysite.com/hello.html -> Redirect to www.mysite.com
Rule 2: Request to www.mysite.com/mypath/* -> Redirect to www.mysite.com/{0}