diff --git a/lib/redmine/wiki_formatting/macros.rb b/lib/redmine/wiki_formatting/macros.rb
index c0f2b22..4ec8c7e 100644
--- a/lib/redmine/wiki_formatting/macros.rb
+++ b/lib/redmine/wiki_formatting/macros.rb
@@ -79,8 +79,16 @@ module Redmine
       
       desc "Include a wiki page. Example:\n\n  !{{include(Foo)}}"
       macro :include do |obj, args|
-        if @project && !@project.wiki.nil?
-          page = @project.wiki.find_page(args.first)
+        if args[1]
+          incproject = Project.find(args[1])
+          if !incproject
+            raise "Project #{args[1]} doesn't exist"
+          end          
+        else
+          incproject = @project
+        end
+        if incproject && !incproject.wiki.nil?
+          page = incproject.wiki.find_page(args.first)
           if page && page.content
             @included_wiki_pages ||= []
             raise 'Circular inclusion detected' if @included_wiki_pages.include?(page.title)