extending a .net library localisation from outside the dll

Question

Say I've got a class library into which I embed a set of string resources. I can have:

Resources.resx
Resources.en-GB.resx
Resources.en-US.resx
etc

Once I've compiled this dll and released it, is there a way users of the dll can add their own localisation for languages i havent supported out of the box, without giving them the src to the dll?

if so, what are the necessary steps that need performing?

Thanks