No, I don't see a fire-symbol anywhere with the "Gnutella Net" Tab open.
Both clients are not firewalled against each other and don't have personal firewalls installed (and also internet-access is available via NAT, but both clients have then the same external IP), but I guess I simply don't understand the problem ;-)

However because we would like to use this private-network for internal sharing we would like to avoid "external" connections as far as possible.

Thanks for helping, lg Clemens