If I understand your setup, you could use 'Individual Start Channels', assigning a start channel to an arch, then after those channels, assign the RBL it's own start channel. Do this for each set of Arches and RBL's. Set up a 'Group' for the RBL's and you can control them individualy or all together. Not sure how many you want to run off of one port, but this way you can run as many as your controller will permit.