php - Regex help (extracting data between hr tags) -

I am trying to remove teaser text within TinyMCE in a PHP CMS In my design & lt; Hr / & gt; tag is not used, so I want to remove the text in the following scenario based on the assumption that Content Administrators will only use to define teaser text:

1. < P> a & lt; Hour / & gt; Remove the content before the tag (Content administrator in the status admin uses the cuttof point as the beginning of teaser text, and then as & gt; ) < / P>

2. 2 & lt; Remove content between hr / & gt; The tag (in which case the content administrator enters teaser text anywhere within the content, and it points to any with the and tag

   What should I use to regex to cover the above?