Profibus DP Ring Topology, Mixing fiber and copper

Has anyone tried successfully in implementing a Profibus DP ring topology by alternating fiber to copper and back to fiber? I know how to use fiber OLMs to establish a ring topology on their own and just branching off of each OLM to hit each slave device. Will there be any issues if I integrate the copper connections to make a larger ring?

In a typical fiber ring topology, my OLM is my single point of failure that could take out every slave device connected to it. I'm wondering if the copper/fiber ring combo idea has worked for others and I can at least make the OLM redundant.

Thanks for any input you may have.