Just make a channel with only a single organization, or alternatively - create a channel with all organizations and then remove the organizations you don't want.
From: "Aleksandr Kochetkov" <aleksandr.kochetkov@...>
Date: 01/09/2020 05:47 PM
Subject: [EXTERNAL] [Hyperledger Fabric] How to achieve channels isolation on RAFT orderers?
Sent by: fabric@...
3 parties, each have a peer and orderer:
peer.a, orderer.a, peer.b, orederer.b, peer.c, orderer.c
Orderers operating in Raft mode.
2 channels exists A-B, B-C.
Goal is to isolate data flow, so organization C don’t have any access to channel A-B, same for A and channel B-C.