diff --git a/cluster/lib/service-module.nix b/cluster/lib/service-module.nix
index 4b30d77..a9dfee8 100644
--- a/cluster/lib/service-module.nix
+++ b/cluster/lib/service-module.nix
@@ -1,6 +1,13 @@
+vars:
 { name, config, lib, ... }:
 with lib;
 
+let
+  notSelf = x: x != vars.hostName;
+
+  filterGroup = builtins.filter notSelf;
+in
+
 {
   options = {
     nodes = mkOption {
@@ -17,10 +24,16 @@ with lib;
       type = with types; attrsOf (oneOf [ str (listOf str) ]);
       default = [];
     };
+    otherNodes = mkOption {
+      description = "Other nodes in the group.";
+      type = with types; attrsOf (listOf str);
+      default = [];
+    };
     nixos = mkOption {
       description = "NixOS configurations per node group.";
       type = with types; attrs;
       default = {};
     };
   };
+  config.otherNodes = builtins.mapAttrs (_: filterGroup) config.nodes;
 }
diff --git a/cluster/lib/services.nix b/cluster/lib/services.nix
index 80c60c6..68f6ca9 100644
--- a/cluster/lib/services.nix
+++ b/cluster/lib/services.nix
@@ -12,7 +12,7 @@ in
 {
   options.services = mkOption {
     description = "Cluster services.";
-    type = with types; attrsOf (submodule (import ./service-module.nix ));
+    type = with types; attrsOf (submodule (import ./service-module.nix config.vars));
     default = {};
   };
   config.out.injectedNixosConfig = lib.flatten (lib.mapAttrsToList (_: getServiceConfigurations) config.services);