If you are asking to share the same storage, it isn't possible to share the same storage between two seperate resouece groups at the same time.
If youare asking for the new server to be added into the cluster and be a possible owner of the resource group, then yes this is possible. You'll have to add the node into the cluster at the OS level first, then open up the control panel -> sql server,
then on the change or remove instance choose maintain the virtual server. You'll be walked through the screens, choose to add your node, etc.
If neither of these are what you were looking to do, please explain the question in more depth.