Sharing I/O Memory

I have an L4 process requesting access to a large chunk (512MB) of physical RAM using l4sigma0_map_iomem(). I am not using l4sigma0_map_mem() because Fiasco is running in a different partition of physical RAM.

I would like to then grant full read/write access to the same memory to a second L4 process, but I'm not sure how to do that. I believe from looking at the sigma0 code that any memory, I/O or RAM, can only be allocated to one L4 process at a time.

It also doesn't look like clans have anything to do with this, other than the possibility of creating some shared memory for an IPC. But that's not really what I want to do, I want both L4 processes to directly access the memory. Is there some way to accomplish this?

Thanks,