diff --git a/src/Bus.Aux.swift b/src/Bus.Aux.swift
index 45cf523..9284e1d 100644
--- a/src/Bus.Aux.swift
+++ b/src/Bus.Aux.swift
@@ -14,13 +14,13 @@ extension Bus {
   }
 
   /// Обрабатываем.
-  static func processKeyValue<Src, Dst>(
+  static func processKeysValue<Src, Dst>(
     _ v: (key: String, value: Any),
-    _ keyIn: String,
+    _ keysIn: Set<String>,
     _ handler: @escaping ((Src) -> Dst?)
   ) -> Dst? {
     guard
-      v.key == keyIn,
+      keysIn.contains(v.key),
       let vIn = v.value as? Src
     else {
       return nil
diff --git a/src/Bus.Processor.swift b/src/Bus.Processor.swift
index edf967e..be3fd14 100644
--- a/src/Bus.Processor.swift
+++ b/src/Bus.Processor.swift
@@ -10,7 +10,16 @@ public extension Bus {
       _ handler: @escaping ((Src) -> Dst?),
       opt: [Option] = []
     ) {
-      Bus.process(keyIn, keyOut, handler, opt: opt, sub: &subscriptions)
+      Bus.process([keyIn], keyOut, handler, opt: opt, sub: &subscriptions)
+    }
+
+    public init(
+      _ keysIn: Set<String>,
+      _ keyOut: String,
+      _ handler: @escaping ((Src) -> Dst?),
+      opt: [Option] = []
+    ) {
+      Bus.process(keysIn, keyOut, handler, opt: opt, sub: &subscriptions)
     }
   }
 }
diff --git a/src/Bus.swift b/src/Bus.swift
index 6f9e162..5eef129 100644
--- a/src/Bus.swift
+++ b/src/Bus.swift
@@ -96,7 +96,7 @@ public extension Bus {
 
 public extension Bus {
   static func process<Src, Dst>(
-    _ keyIn: String,
+    _ keysIn: Set<String>,
     _ keyOut: String,
     _ handler: @escaping ((Src) -> Dst?),
     opt: [Option] = [],
@@ -108,7 +108,7 @@ public extension Bus {
     // Async.
     if isAsync {
       subscription = Service.singleton.events
-      .compactMap { processKeyValue($0, keyIn, handler) }
+      .compactMap { processKeysValue($0, keysIn, handler) }
       .receive(on: DispatchQueue.main)
       .sink { vOut in Service.singleton.send(keyOut, vOut) }
     }
@@ -116,7 +116,7 @@ public extension Bus {
     // Sync.
     if !isAsync {
       subscription = Service.singleton.events
-      .compactMap { processKeyValue($0, keyIn, handler) }
+      .compactMap { processKeysValue($0, keysIn, handler) }
       .sink { vOut in Service.singleton.send(keyOut, vOut) }
     }