Hi Timo
I am picking this up as part of OFN’s ‘global gardening’ process. I am involved with OFN UK and helping to co-ordinate progress on OFN Germany. There is a test instance set up in Germany here and you are welcome to play with it.
To answer your questions:
• In the UK we have one instance and set up discrete OFN groups within that instance.
• We are in the early stages of exploring a single global instance which would solve the issues of national boundaries. You are welcome to join the conversation here