--- a/modules/hosts.nix
+++ b/modules/hosts.nix
@@ -1,12 +1,15 @@
 {
   lib,
   fleetLib,
+  config,
   ...
 }: let
   inherit (fleetLib.modules) mkFleetGeneratorDefault;
   inherit (fleetLib.types) mkHostsType mkDataType;
   inherit (lib.options) mkOption;
   inherit (lib.types) str listOf attrsOf submodule;
+  inherit (lib.attrsets) mapAttrsToList mapAttrs;
+  inherit (lib.lists) flatten groupBy;
 in {
   options = {
     data = mkOption {
@@ -35,6 +38,10 @@
         Usually used to persist fleet data between runs.
       '';
     };
+    taggedWith = mkOption {
+      type = attrsOf (listOf str);
+      internal = true;
+    };
     hosts = mkOption {
       type = mkHostsType ({config, ...}: {
         options = {
@@ -75,5 +82,10 @@
       description = "Configurations of individual hosts";
     };
   };
+  config.taggedWith = let
+    hostTagList = flatten (mapAttrsToList (hostname: host: map (tag: {inherit hostname tag;}) host.tags) config.hosts);
+    grouped = mapAttrs (_: hosts: lib.map (pair: pair.hostname) hosts) (groupBy (elem: elem.tag) hostTagList);
+  in
+    grouped;
   _file = ./meta.nix;
 }