You need to add the bookmarks to the word doc directly to be able to search and find the section.
Some sample code to find and scroll to the bookmark in c#, if need VBA you'll have to port.
Microsoft.Office.Interop.Word.Application wApp = new Microsoft.Office.Interop.Word.Application();
wApp.Visible = true;
Microsoft.Office.Interop.Word._Document doc = wApp.Documents.Open("yourhelpdocpath");
if (null != doc) {
if (doc.Bookmarks.Exists("yourRadioButtonBookmarkSelection")){
Microsoft.Office.Interop.Word.Bookmark mark = doc.Bookmarks["yourRadioButtonBookmarkSelection"];
Microsoft.Office.Interop.Word.Range rng = mark.Range;
wApp.ActiveWindow.ScrollIntoView(rng);
}
}
Tested using local word document, though I believe it should work through server call long as you can definitely get the document.