Change pirates so that they do not shoot at ships that have only thrust and power for their system blocks, only basic hull and decor. blocks as structure blocks, and are less than a certain mass (configurable in the server cfg file). Unless you are the only ship in the area; then they will still shoot at you. If there are other nearby ships that do not meet this criteria, then they will focus on those instead.
Or, have a % chance for each pirate ship that it will not shoot at ships that meet this criteria. It is determined if it is one of those pirate ships when it spawns.
Or, have a % chance for each pirate ship that it will not shoot at ships that meet this criteria. It is determined if it is one of those pirate ships when it spawns.