You should have no problems with the code that Ben Nye
supplied. By the way, the difference between "Normal Page" and "Page Group" is only that if the page is set as "Page Group", it redirects to its first subpage when you try to access it.
You could try adding this line in your JoinNewsImgBtnSubmit_Click
I don't think that it is necessary to execute additional pages to access your page.
the Telerik team