How to avoid the posts of the main site in RECENT GLOBAL POST plugin

Hi again. I'd like to avoid the posts of the main site could be showed in "RECENT GLOBAL POSTS" widget.

I consulted some code in the widget and see that $blog_title contains the name of the blog, in my case the main blog name is "NOTICIAS".

So the issue is to avoid all variable $blog_title posts which contains the value "NOTICIAS".

I made ??some attempts, but I have not been able to encode correctly.

Any help please?