Thank you @mdunphy!
That would have been the choice for earlier NEMO versions. However NEMO 5 is supposed to be capable of crossing the cyclic boundary with a child grid - and it somehow is, at least when using intel compilers.
Has anyone ever successfully set up such a configuration and run successfully using gnu compilers? If so, I would be very much interested in respective details on compiler versions, flags, libraries etc.
Thank you.