diff --git a/classes/deck/deck.gd b/classes/deck/deck.gd
index 5d603f5..d142835 100644
--- a/classes/deck/deck.gd
+++ b/classes/deck/deck.gd
@@ -349,6 +349,19 @@ func send_event(event_name: StringName, event_data: Dictionary = {}) -> void:
 		node._event_received(event_name, event_data)
 
 
+func get_referenced_groups() -> Array[String]:
+	# this is expensive
+	# recursively returns a list of all groups referenced by this deck
+	var res: Array[String] = []
+	for node_id: String in nodes:
+		var node := get_node(node_id)
+		if node.node_type != "group_node":
+			continue
+		res.append(node.group_id)
+		res.append_array(DeckHolder.get_deck(node.group_id).get_referenced_groups())
+	return res
+
+
 ## Returns a [Dictionary] representation of this deck.
 func to_dict(with_meta: bool = true, group_ids: Array = []) -> Dictionary:
 	var inner := {
diff --git a/classes/deck/deck_holder.gd b/classes/deck/deck_holder.gd
index b0b1688..132d3eb 100644
--- a/classes/deck/deck_holder.gd
+++ b/classes/deck/deck_holder.gd
@@ -98,9 +98,18 @@ static func close_group_instance(group_id: String, instance_id: String) -> void:
 		decks.erase(group_id)
 
 
+static func close_all_group_instances(group_id: String) -> void:
+	if decks.get(group_id) is Dictionary:
+		decks.erase(group_id)
+
+
 ## Unloads a deck.
 static func close_deck(deck_id: String) -> void:
 	if decks.get(deck_id) is Deck:
+		var deck: Deck = decks[deck_id] as Deck
+		var groups := deck.get_referenced_groups()
+		for group in groups:
+			close_all_group_instances(group)
 		decks.erase(deck_id)