--- a/browser/themes/moz.build
+++ b/browser/themes/moz.build
@@ -10,8 +10,17 @@ with Files("**"):
 toolkit = CONFIG['MOZ_WIDGET_TOOLKIT']
 
 if toolkit == 'cocoa':
     DIRS += ['osx']
 elif toolkit in ('gtk2', 'gtk3'):
     DIRS += ['linux']
 else:
     DIRS += ['windows']
+
+with Files('osx/**'):
+    SCHEDULES.exclusive = ['macosx']
+
+with Files('linux/**'):
+    SCHEDULES.exclusive = ['linux']
+
+with Files('windows/**'):
+    SCHEDULES.exclusive = ['windows']

--- a/mobile/android/moz.build
+++ b/mobile/android/moz.build
@@ -1,16 +1,17 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 with Files('**'):
     BUG_COMPONENT = ('Firefox for Android', 'Build Config & IDE Support')
+    SCHEDULES.exclusive = ['android']
 
 with Files('bouncer/**'):
     BUG_COMPONENT = ('Firefox for Android', 'Distributions')
 
 with Files('branding/**'):
     BUG_COMPONENT = ('Firefox for Android', 'General')
 
 with Files('build/**'):

--- a/moz.build
+++ b/moz.build
@@ -31,16 +31,17 @@ with Files('mach'):
 with Files('*moz*'):
     BUG_COMPONENT = ('Core', 'Build Config')
 
 with Files('GNUmakefile'):
     BUG_COMPONENT = ('Core', 'Build Config')
 
 with Files('*gradle*'):
     BUG_COMPONENT = ('Firefox for Android', 'Build Config & IDE Support')
+    SCHEDULES.exclusive = ['android']
 
 with Files('**/l10n.toml'):
     BUG_COMPONENT = ('Core', 'Localization')
     FINAL = True
 
 with Files('README.txt'):
     BUG_COMPONENT = ('Core', 'General')