This is how I did it in the end:
add network name Net-192.168.111.0 subnet4 192.168.111.0 mask-length4 24 color cyan
add network name Net-192.168.113.0 subnet4 192.168.113.0 mask-length4 24 color cyan
add network name Net-192.168.114.0 subnet4 192.168.114.0 mask-length4 24 color cyan
add network name Net-192.168.116.0 subnet4 192.168.116.0 mask-length4 24 color cyan
add network name Net-192.168.117.0 subnet4 192.168.117.0 mask-length4 24 color cyan
add network name Net-192.168.119.0 subnet4 192.168.119.0 mask-length4 24 color cyan
add network name Net-192.168.122.0 subnet4 192.168.122.0 mask-length4 24 color cyan
add network name Net-192.168.123.0 subnet4 192.168.123.0 mask-length4 24 color cyan
add network name Net-192.168.124.0 subnet4 192.168.124.0 mask-length4 24 color cyan
add network name Net-192.168.125.0 subnet4 192.168.125.0 mask-length4 24 color cyan
add network name Net-192.168.126.0 subnet4 192.168.126.0 mask-length4 24 color cyan
add network name Net-192.168.131.0 subnet4 192.168.131.0 mask-length4 24 color cyan
add network name Net-192.168.134.0 subnet4 192.168.134.0 mask-length4 24 color cyan
add group name Internal-Nets color cyan
set group name Internal-Nets members.add.1 Net-192.168.111.0 members.add.2 Net-192.168.113.0 members.add.3 Net-192.168.114.0 members.add.4 Net-192.168.116.0 members.add.5 Net-192.168.117.0 members.add.6 Net-192.168.119.0 members.add.7 Net-192.168.122.0 members.add.8 Net-192.168.123.0 members.add.9 Net-192.168.124.0 members.add.10 Net-192.168.125.0 members.add.11 Net-192.168.126.0 members.add.12 Net-192.168.131.0 members.add.13 Net-192.168.134.0
The set group command above (the last line) is one line (of 450 characters).