diff --git a/classes/deck/deck.gd b/classes/deck/deck.gd
index ca3d553..5f19b37 100644
--- a/classes/deck/deck.gd
+++ b/classes/deck/deck.gd
@@ -39,11 +39,13 @@ signal node_added(node: DeckNode)
 ## Emitted when a node has been removed from this deck.
 signal node_removed(node: DeckNode)
 
+#region group signals
 signal node_added_to_group(node: DeckNode, assign_id: String, assign_to_self: bool, deck: Deck)
 signal node_removed_from_group(node_id: String, remove_connections: bool, deck: Deck)
 signal nodes_connected_in_group(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int, deck: Deck)
 signal nodes_disconnected_in_group(from_node_id: String, to_node_id: String, from_output_port: int, to_input_port: int, deck: Deck)
-
+signal node_port_value_updated(node_id: String, port_idx: int, new_value: Variant, deck: Deck)
+#endregion
 
 ## Instantiate a node by its' [member DeckNode.node_type] and add it to this deck.[br]
 ## See [method add_node_inst] for parameter descriptions.
@@ -74,6 +76,12 @@ func add_node_inst(node: DeckNode, assign_id: String = "", assign_to_self: bool
 	if is_group && emit_group_signals:
 		node_added_to_group.emit(node, assign_id, assign_to_self, self)
 
+	node.port_value_updated.connect(
+		func(port_idx: int, new_value: Variant):
+			if is_group && emit_group_signals:
+				node_port_value_updated.emit(node._id, port_idx, new_value, self)
+			)
+
 	return node
 
 
diff --git a/classes/deck/deck_holder.gd b/classes/deck/deck_holder.gd
index b9636d3..b5ef9fb 100644
--- a/classes/deck/deck_holder.gd
+++ b/classes/deck/deck_holder.gd
@@ -45,6 +45,7 @@ static func add_group_from_dict(data: Dictionary, deck_id: String, instance_id:
 	group.node_removed_from_group.connect(DeckHolder._on_node_removed_from_group)
 	group.nodes_connected_in_group.connect(DeckHolder._on_nodes_connected_in_group)
 	group.nodes_disconnected_in_group.connect(DeckHolder._on_nodes_disconnected_in_group)
+	group.node_port_value_updated.connect(DeckHolder._on_node_port_value_updated)
 	return group
 
 
@@ -64,6 +65,7 @@ static func add_empty_group() -> Deck:
 	group.node_removed_from_group.connect(DeckHolder._on_node_removed_from_group)
 	group.nodes_connected_in_group.connect(DeckHolder._on_nodes_connected_in_group)
 	group.nodes_disconnected_in_group.connect(DeckHolder._on_nodes_disconnected_in_group)
+	group.node_port_value_updated.connect(DeckHolder._on_node_port_value_updated)
 	return group
 
 
@@ -158,4 +160,16 @@ static func _on_nodes_disconnected_in_group(from_node_id: String, to_node_id: St
 		instance.disconnect_nodes(from_node_id, to_node_id, from_output_port, to_input_port)
 		instance.emit_group_signals = true
 
+
+static func _on_node_port_value_updated(node_id: String, port_idx: int, new_value: Variant, deck: Deck) -> void:
+	var group_id := deck.id
+	for instance_id: String in decks[group_id]:
+		if instance_id == deck.instance_id:
+			continue
+
+		var instance: Deck = get_group_instance(group_id, instance_id)
+		instance.emit_group_signals = false
+		instance.get_node(node_id).get_all_ports()[port_idx].set_value_no_signal(new_value)
+		instance.emit_group_signals = true
+
 #endregion
diff --git a/classes/deck/deck_node.gd b/classes/deck/deck_node.gd
index 4f60b17..74ae61b 100644
--- a/classes/deck/deck_node.gd
+++ b/classes/deck/deck_node.gd
@@ -64,6 +64,8 @@ signal incoming_connection_added(from_port: int)
 ## Emitted when a connection to this node has been removed.
 signal incoming_connection_removed(from_port: int)
 
+signal port_value_updated(port_idx: int, new_value: Variant)
+
 
 ## Add an input port to this node. Usually only used at initialization.
 func add_input_port(type: DeckType.Types, label: String, descriptor: String = "") -> void:
@@ -85,10 +87,15 @@ func add_port(type: DeckType.Types, label: String, port_type: PortType, index_of
 	var port := Port.new(type, label, ports.size(), port_type, index_of_type, descriptor)
 	ports.append(port)
 	port_added.emit(ports.size() - 1)
+	port.value_updated.connect(
+		func(new_value: Variant) -> void:
+			port_value_updated.emit(port.index, new_value)
+	)
 	ports_updated.emit()
 
 
 ## Remove a port from this node.
+## @deprecated
 func remove_port(port_idx: int) -> void:
 	outgoing_connections.erase(port_idx)
 	incoming_connections.erase(port_idx)
diff --git a/classes/deck/port.gd b/classes/deck/port.gd
index 000c822..4387780 100644
--- a/classes/deck/port.gd
+++ b/classes/deck/port.gd
@@ -25,7 +25,7 @@ var index_of_type: int
 var index: int
 
 ## The value of this port.
-var value: Variant: set = set_value
+var value: Variant
 
 signal value_updated(new_value: Variant)
 
@@ -50,10 +50,13 @@ func _init(
 
 
 func set_value(v: Variant) -> void:
+	set_value_no_signal(v)
+	value_updated.emit(value)
+
+
+func set_value_no_signal(v: Variant) -> void:
 	if v is Callable:
 		value = v.call()
-		value_updated.emit(value)
 		return
 
 	value = v
-	value_updated.emit(value)