diff --git a/crates/brk_computer/src/vecs/stateful/addresstype_to_typeindex_set.rs b/crates/brk_computer/src/vecs/stateful/addresstype_to_typeindex_set.rs
new file mode 100644
index 000000000..640398383
--- /dev/null
+++ b/crates/brk_computer/src/vecs/stateful/addresstype_to_typeindex_set.rs
@@ -0,0 +1,47 @@
+use std::{collections::BTreeSet, mem};
+
+use brk_core::TypeIndex;
+use derive_deref::{Deref, DerefMut};
+
+use super::ByAddressType;
+
+#[derive(Debug, Deref, DerefMut)]
+pub struct AddressTypeToTypeIndexSet(ByAddressType<BTreeSet<TypeIndex>>);
+
+impl AddressTypeToTypeIndexSet {
+    pub fn merge(mut self, mut other: Self) -> Self {
+        Self::merge_(&mut self.p2pk65, &mut other.p2pk65);
+        Self::merge_(&mut self.p2pk33, &mut other.p2pk33);
+        Self::merge_(&mut self.p2pkh, &mut other.p2pkh);
+        Self::merge_(&mut self.p2sh, &mut other.p2sh);
+        Self::merge_(&mut self.p2wpkh, &mut other.p2wpkh);
+        Self::merge_(&mut self.p2wsh, &mut other.p2wsh);
+        Self::merge_(&mut self.p2tr, &mut other.p2tr);
+        Self::merge_(&mut self.p2a, &mut other.p2a);
+        self
+    }
+
+    fn merge_(own: &mut BTreeSet<TypeIndex>, other: &mut BTreeSet<TypeIndex>) {
+        if own.len() >= other.len() {
+            own.append(other);
+        } else {
+            other.append(own);
+            mem::swap(own, other);
+        }
+    }
+}
+
+impl Default for AddressTypeToTypeIndexSet {
+    fn default() -> Self {
+        Self(ByAddressType {
+            p2pk65: BTreeSet::default(),
+            p2pk33: BTreeSet::default(),
+            p2pkh: BTreeSet::default(),
+            p2sh: BTreeSet::default(),
+            p2wpkh: BTreeSet::default(),
+            p2wsh: BTreeSet::default(),
+            p2tr: BTreeSet::default(),
+            p2a: BTreeSet::default(),
+        })
+    }
+}