Show Excerpt using tag

I am using this code: https://github.com/itthinx/groups-excerpts

I would like the code modified so that rather than the excerpt being returned, the content up to the <!–more–> tag is returned. I do not know how to change this line to make this happen.

$result .= apply_filters( ‘get_the_excerpt’, $post->post_excerpt );

Also, I need all formatting to be sent through. Right now all line feeds are being stripped.

https://www.ads-software.com/plugins/groups/