diff --git a/cluster/lib/inject-nixos-config.nix b/cluster/lib/inject-nixos-config.nix
index 6e5add1..4523b96 100644
--- a/cluster/lib/inject-nixos-config.nix
+++ b/cluster/lib/inject-nixos-config.nix
@@ -2,9 +2,9 @@
 with lib;
 
 {
-  options.out.injectNixosConfig = mkOption {
-    description = "NixOS configuration to inject into the given host.";
-    type = with types; functionTo raw;
+  options.out = mkOption {
+    description = "Output functions.";
+    type = with types; lazyAttrsOf (functionTo raw);
     default = const [];
   };
 }
diff --git a/cluster/lib/services.nix b/cluster/lib/services.nix
index b500f1b..4e9f8bc 100644
--- a/cluster/lib/services.nix
+++ b/cluster/lib/services.nix
@@ -39,7 +39,11 @@ in
     default = {};
   };
 
-  config.out.injectNixosConfig = hostName: (lib.flatten (lib.mapAttrsToList (getHostConfigurations hostName) config.services)) ++ [
-    introspectionModule
-  ];
+  config.out = {
+    injectNixosConfigForServices = services: hostName: (lib.flatten (lib.mapAttrsToList (getHostConfigurations hostName) (lib.getAttrs services config.services))) ++ [
+      introspectionModule
+    ];
+
+    injectNixosConfig = config.out.injectNixosConfigForServices (lib.attrNames config.services);
+  };
 }