You can define a InitializableModule, inherit it from IInitializableHttpModule.

Then bind you event like:

public void InitializeHttpEvents(HttpApplication application)
{
       application.PreRequestHandlerExecute += this.ApplicationOnBeginRequest;
}

Now, inside your ApplicationOnBeginRequest method

private void ApplicationOnBeginRequest(object sender, EventArgs eventArgs)
{
     var contentRouteHelper = ServiceLocator.Current.GetInstance<IContentRouteHelper>();
     if (contentRouteHelper?.Content is PageData myPage)
     {
          var cat = myPage.Category.First();
          var redirect = contentRouteHelper.Content.ParentLink + cat.ToString() + contentRouteHelper.ContentLink;
          HttpContext.Current.Response.Redirect(redirectUrl);
     }
     
}

1. Check if the request is for PageData type (as in above example)
2. Get your category (I tried only first category).
3. Format your url then redirect to it.

Note: This is high level idea only. Put proper null checks and exception handling.

Thanks & Regards

Praful Jangid