Facebook post like with custom link to be liked?

Hello,

I am looking for a plugin, that would add a Facebook like button under a post, but also allow to set a custom link (Custom Field?) to be liked.

Example: I have a post on Facebook that is of the same content as my WordPress entry, and I would like to consolidate likes – so when someone cliks “like” under my WP entry he actually likes the FB post.

Have you seen such a plugin?
Or maybe you have another idea?

Thanks,
Janko