Index: wp-admin/network/admin.php
===================================================================
--- wp-admin/network/admin.php	(revision 17666)
+++ wp-admin/network/admin.php	(working copy)
@@ -15,8 +15,11 @@
 if ( ! is_multisite() )
 	wp_die( __( 'Multisite support is not enabled.' ) );
 
-if ( ( $current_blog->domain != $current_site->domain ) || ( $current_blog->path != $current_site->path ) ) {
+$redirect_network_admin_request = ( ( $current_blog->domain != $current_site->domain ) || ( $current_blog->path != $current_site->path ) );
+$redirect_network_admin_request = apply_filters( 'redirect_network_admin_request', $redirect_network_admin_request );
+if ( $redirect_network_admin_request ) {
 	wp_redirect( network_admin_url() );
 	exit;
 }
+unset( $redirect_network_admin_request );
 ?>
Index: wp-admin/user/admin.php
===================================================================
--- wp-admin/user/admin.php	(revision 17666)
+++ wp-admin/user/admin.php	(working copy)
@@ -16,8 +16,12 @@
 	exit;
 }
 
-if ( ( $current_blog->domain != $current_site->domain ) || ( $current_blog->path != $current_site->path ) ) {
+$redirect_user_admin_request = ( ( $current_blog->domain != $current_site->domain ) || ( $current_blog->path != $current_site->path ) );
+$redirect_user_admin_request = apply_filters( 'redirect_user_admin_request', $redirect_user_admin_request );
+if ( $redirect_user_admin_request ) {
 	wp_redirect( user_admin_url() );
 	exit;
 }
+unset( $redirect_user_admin_request );
+
 ?>