diff --git a/bumble/profiles/hap.py b/bumble/profiles/hap.py
index 8432ef1..d4abd12 100644
--- a/bumble/profiles/hap.py
+++ b/bumble/profiles/hap.py
@@ -236,6 +236,8 @@ class HearingAccessService(gatt.TemplateService):
     preset_records: Dict[int, PresetRecord]  # key is the preset index
     read_presets_request_in_progress: bool
 
+    other_server_in_binaural_set: Optional[HearingAccessService] = None
+
     preset_changed_operations_history_per_device: Dict[
         Address, List[PresetChangedOperation]
     ]
@@ -513,7 +515,7 @@ class HearingAccessService(gatt.TemplateService):
         for connection in self.currently_connected_clients:
             await self.notify_active_preset_for_connection(connection)
 
-    async def set_active_preset(self, connection: Connection, value: bytes) -> None:
+    async def set_active_preset(self, value: bytes) -> None:
         index = value[1]
         preset = self.preset_records.get(index, None)
         if (
@@ -530,10 +532,10 @@ class HearingAccessService(gatt.TemplateService):
         self.active_preset_index = index
         await self.notify_active_preset()
 
-    async def _on_set_active_preset(self, connection: Connection, value: bytes):
-        await self.set_active_preset(connection, value)
+    async def _on_set_active_preset(self, _: Connection, value: bytes):
+        await self.set_active_preset(value)
 
-    async def set_next_or_previous_preset(self, connection: Connection, is_previous):
+    async def set_next_or_previous_preset(self, is_previous):
         '''Set the next or the previous preset as active'''
 
         if self.active_preset_index == 0x00:
@@ -563,48 +565,47 @@ class HearingAccessService(gatt.TemplateService):
             self.active_preset_index = first_preset.index
         await self.notify_active_preset()
 
-    async def _on_set_next_preset(
-        self, connection: Connection, __value__: bytes
-    ) -> None:
-        await self.set_next_or_previous_preset(connection, False)
+    async def _on_set_next_preset(self, _: Connection, __value__: bytes) -> None:
+        await self.set_next_or_previous_preset(False)
 
-    async def _on_set_previous_preset(
-        self, connection: Connection, __value__: bytes
-    ) -> None:
-        await self.set_next_or_previous_preset(connection, True)
+    async def _on_set_previous_preset(self, _: Connection, __value__: bytes) -> None:
+        await self.set_next_or_previous_preset(True)
 
     async def _on_set_active_preset_synchronized_locally(
-        self, connection: Connection, value: bytes
+        self, _: Connection, value: bytes
     ):
         if (
             self.server_features.preset_synchronization_support
-            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_SUPPORTED
+            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_NOT_SUPPORTED
         ):
             raise att.ATT_Error(ErrorCode.PRESET_SYNCHRONIZATION_NOT_SUPPORTED)
-        await self.set_active_preset(connection, value)
-        # TODO (low priority) inform other server of the change
+        await self.set_active_preset(value)
+        if self.other_server_in_binaural_set:
+            await self.other_server_in_binaural_set.set_active_preset(value)
 
     async def _on_set_next_preset_synchronized_locally(
-        self, connection: Connection, __value__: bytes
+        self, _: Connection, __value__: bytes
     ):
         if (
             self.server_features.preset_synchronization_support
-            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_SUPPORTED
+            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_NOT_SUPPORTED
         ):
             raise att.ATT_Error(ErrorCode.PRESET_SYNCHRONIZATION_NOT_SUPPORTED)
-        await self.set_next_or_previous_preset(connection, False)
-        # TODO (low priority) inform other server of the change
+        await self.set_next_or_previous_preset(False)
+        if self.other_server_in_binaural_set:
+            await self.other_server_in_binaural_set.set_next_or_previous_preset(False)
 
     async def _on_set_previous_preset_synchronized_locally(
-        self, connection: Connection, __value__: bytes
+        self, _: Connection, __value__: bytes
     ):
         if (
             self.server_features.preset_synchronization_support
-            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_SUPPORTED
+            == PresetSynchronizationSupport.PRESET_SYNCHRONIZATION_IS_NOT_SUPPORTED
         ):
             raise att.ATT_Error(ErrorCode.PRESET_SYNCHRONIZATION_NOT_SUPPORTED)
-        await self.set_next_or_previous_preset(connection, True)
-        # TODO (low priority) inform other server of the change
+        await self.set_next_or_previous_preset(True)
+        if self.other_server_in_binaural_set:
+            await self.other_server_in_binaural_set.set_next_or_previous_preset(True)
 
 
 # -----------------------------------------------------------------------------