iPad apps that launch websites from with the app

New Contributor

We have iPads that we restrict to specific apps and do not allow Safari, but some apps can launch web pages and YouTube from with the app.  For instance an App has a menu with an "about" that has a link to their site which has a link to YouTube and the student can watch YouTube videos and it is all through the App they are using and does not open Safari.  I have been unable to find a way to block this and wondering if anyone else has come across this problem and found  solution?