Assign external 3D to GLWidget

Hi, I have an OpenGL graphics library and I want assign all OpenGL operations to a QGLWidget. I mean I want all 3D to be displayed in QGLWidget. The library is OpenSource so I can add my custom initialization routine to it. It doesn't need to be crossplatform and may work only in windows. Sorry, but I don't know the right approach how this could be implemented. Any thoughts?

Maybe, there is an OpenGL routine that binds all OpenGL functions to a specific window and maybe there is some kind an OpenGL handle I can obtain within QGLWidget? Than I think I can link them together.