Hi, by default amidiauto makes connections only between the software and hardware ports, however, it can make the desired connections if they are explicitly defined in /etc/amidiauto.conf, see Patchbox and ORAC for some details how it works. (you probably already have 1.01 version, so you don’t have to install manually as shown in my post)
Here’s a config that should work for you, feel free to adjust 
[allow]
* <-> * # Allow automatically connecting hw and sw ports
OP-1 <-> OP-Z # Connect OP-1 and OP-Z in both directions.
# Use <- or -> instead to connect in only one direction
# a -> b would cause output from a to be connected to b input.
pisound -> OP-1
After changing the config, restart amidiauto:
sudo systemctl restart amidiauto