Different versions of library: Is it possible?

All,
I guess its not possible, but is there a way to 'Add Reference' to different versions of same DLL in .Net?
I have SampleLib.DLL (Version 1.0) and SampleLib.DLL (Version 2.0) and i want some users to be able to use version 1.0 and others version 2.0. Is there a way to achieve this? Please suggest

thanks!