diff --git a/lib/application_manager.rb b/lib/application_manager.rb
index c525036..508b813 100644
--- a/lib/application_manager.rb
+++ b/lib/application_manager.rb
@@ -235,11 +235,11 @@ class W3DHub
       end
     end
 
-    def join_server(app_id, channel, server, password = nil)
-      if installed?(app_id, channel) && Store.settings[:server_list_username].to_s.length.positive?
+    def join_server(app_id, channel, server, username = Store.settings[:server_list_username], password = nil, multi = false)
+      if installed?(app_id, channel) && username.to_s.length.positive?
         run(
           app_id, channel,
-          "+connect #{server.address}:#{server.port} +netplayername #{Store.settings[:server_list_username]}#{password ? " +password \"#{password}\"" : ""}"
+          "+connect #{server.address}:#{server.port} +netplayername #{username}#{password ? " +password \"#{password}\"" : ""}#{multi ? " +multi" : ""}"
         )
       end
     end
diff --git a/lib/common.rb b/lib/common.rb
index 953cb53..fc1dc6e 100644
--- a/lib/common.rb
+++ b/lib/common.rb
@@ -81,15 +81,19 @@ class W3DHub
         )
       end
 
-      def self.join_server(server, password)
+      def self.join_server(server:, username: Store.settings[:server_list_username], password: nil, multi: false)
         if (
           (server.status.password && password.length.positive?) ||
           !server.status.password) &&
-           Store.settings[:server_list_username].to_s.length.positive?
+           username.to_s.length.positive?
 
           Store.application_manager.join_server(
             server.game,
-            server.channel, server, password
+            server.channel,
+            server,
+            username,
+            password,
+            multi
           )
         else
           CyberarmEngine::Window.instance.push_state(W3DHub::States::MessageDialog, type: "?", title: "?", message: "?")
diff --git a/lib/pages/server_browser.rb b/lib/pages/server_browser.rb
index 2ab3bc4..b1a11a2 100644
--- a/lib/pages/server_browser.rb
+++ b/lib/pages/server_browser.rb
@@ -410,11 +410,11 @@ class W3DHub
                         if server.status.password
                           W3DHub.prompt_for_password(
                             accept_callback: proc do |password|
-                              W3DHub.join_server(server, password)
+                              W3DHub.join_server(server: server, password: password)
                             end
                           )
                         else
-                          W3DHub.join_server(server, nil)
+                          W3DHub.join_server(server: server)
                         end
                       end
                     )
@@ -422,18 +422,24 @@ class W3DHub
                     if server.status.password
                       W3DHub.prompt_for_password(
                         accept_callback: proc do |password|
-                          W3DHub.join_server(server, password)
+                          W3DHub.join_server(server: server, password: password)
                         end
                       )
                     else
-                      W3DHub.join_server(server, nil)
+                      W3DHub.join_server(server: server)
                     end
                   end
                 end
 
                 if W3DHUB_DEVELOPER
-                  list_box(items: (1..12).to_a.map(&:to_s), margin_left: 16, width: 72, tip: "Number of game clients", enabled: (game_installed && !game_updatable), **TESTING_BUTTON)
-                  button "Multijoin", tip: "Launch multiple clients with configured username_\#{number}", enabled: (game_installed && !game_updatable), **TESTING_BUTTON
+                  client_instances = list_box(items: (1..12).to_a.map(&:to_s), margin_left: 16, width: 72, tip: "Number of game clients", enabled: (game_installed && !game_updatable), **TESTING_BUTTON)
+                  button("Multijoin", tip: "Launch multiple clients with configured username_\#{number}", enabled: (game_installed && !game_updatable), **TESTING_BUTTON) do
+                    username = Store.settings[:server_list_username]
+
+                    client_instances.value.to_i.times do |i|
+                      W3DHub.join_server(server: server, username: format("%s_%d", username, i), multi: true)
+                    end
+                  end
                 end
 
                 flow(fill: true)