Edit links on excerpt and "read more"

I was wondering if it is possible to change the “read more” links, so instead of redirecting to the post, it redirects to where the post comes from?

Its because i have a plugin installed, that gathers posts from multiple sites, using RSS feeds. So i when a user clicks on the excerpt or “read more”, he/she must be redirected to where the post originally came from. I know that the link info is in the post, cause when i click the excerpt it directs me to the post (on my site) and from there i can click “read more” and im forwarded to the original post located on the authors blog/site.

Hope someone can help me – maybe just tell me in which file the code for handling this is located.