diff --git a/commands2/parallelcommandgroup.py b/commands2/parallelcommandgroup.py
index 9645757..1a27779 100644
--- a/commands2/parallelcommandgroup.py
+++ b/commands2/parallelcommandgroup.py
@@ -49,7 +49,9 @@ def addCommands(self, *commands: Command):
         for command in commands:
             in_common = command.getRequirements().intersection(self.requirements)
             if in_common:
-                requirements_str = ", ".join([s.getName() for s in command.getRequirements()])
+                requirements_str = ", ".join(
+                    [s.getName() for s in in_common]
+                )
                 raise IllegalCommandUse(
                     f"Command {command.getName()} could not be added to this ParallelCommandGroup"
                     f" because the subsystems [{requirements_str}] are already required in this command."
diff --git a/commands2/paralleldeadlinegroup.py b/commands2/paralleldeadlinegroup.py
index 967a4c2..7fb4f9a 100644
--- a/commands2/paralleldeadlinegroup.py
+++ b/commands2/paralleldeadlinegroup.py
@@ -85,7 +85,9 @@ def addCommands(self, *commands: Command):
         for command in commands:
             in_common = command.getRequirements().intersection(self.requirements)
             if in_common:
-                requirements_str = ", ".join([s.getName() for s in command.getRequirements()])
+                requirements_str = ", ".join(
+                    [s.getName() for s in in_common]
+                )
                 raise IllegalCommandUse(
                     f"Command {command.getName()} could not be added to this ParallelCommandGroup"
                     f" because the subsystems [{requirements_str}] are already required in this command."
diff --git a/commands2/parallelracegroup.py b/commands2/parallelracegroup.py
index 6b04da6..04f2112 100644
--- a/commands2/parallelracegroup.py
+++ b/commands2/parallelracegroup.py
@@ -51,7 +51,9 @@ def addCommands(self, *commands: Command):
         for command in commands:
             in_common = command.getRequirements().intersection(self.requirements)
             if in_common:
-                requirements_str = ", ".join([s.getName() for s in command.getRequirements()])
+                requirements_str = ", ".join(
+                    [s.getName() for s in in_common]
+                )
                 raise IllegalCommandUse(
                     f"Command {command.getName()} could not be added to this ParallelCommandGroup"
                     f" because the subsystems [{requirements_str}] are already required in this command."