diff --git a/cove-input/src/lib.rs b/cove-input/src/lib.rs
index c89a689..d3963ee 100644
--- a/cove-input/src/lib.rs
+++ b/cove-input/src/lib.rs
@@ -3,3 +3,9 @@ mod keys;
 
 pub use input::*;
 pub use keys::*;
+
+pub trait Group {
+    type Action;
+
+    fn action(&self, input: &mut Input) -> Option<Self::Action>;
+}