diff --git a/fsfwgen/events/event_parser.py b/fsfwgen/events/event_parser.py
index ed4eb89..6c7b333 100644
--- a/fsfwgen/events/event_parser.py
+++ b/fsfwgen/events/event_parser.py
@@ -1,4 +1,5 @@
 import re
+import sys
 import logging
 from pathlib import Path
 from typing import List, Optional, Dict
@@ -70,8 +71,9 @@ class EventParser(FileParser):
         self.set_moving_window_mode(moving_window_size)
         self.interfaces = interface_list
         self.count = 0
-        self.subsystem_id = 0
-        self.current_id = 0
+        self.subsystem_id = None
+        self.current_id = None
+        self.current_file = None
         self.mib_table: EventDictT = dict()
         self.obsw_root_path: Optional[Path] = None
         self.last_lines = ["", "", ""]
@@ -89,6 +91,10 @@ class EventParser(FileParser):
         *args,
         **kwargs,
     ):
+        if file_name != self.current_file:
+            self.current_file = file_name
+            self.subsystem_id = None
+            self.current_id = None
         subsystem_id_assignment_match = re.search(
             rf"{SUBSYSTEM_ID_NAMESPACE}::([A-Z_0-9]*)",
             moving_window[self.moving_window_center_idx],
@@ -155,6 +161,9 @@ class EventParser(FileParser):
             elif meta.type == MetaType.DESC:
                 description = meta.value
         if event_full_match:
+            if self.subsystem_id is None:
+                _LOGGER.error("Subsystem ID not set, cannot parse event")
+                sys.exit(1)
             name = event_match.group(EVENT_NAME_IDX)
             if macro_api_match:
                 full_id = (self.subsystem_id * 100) + self.return_number_from_string(