[Dovecot] Using global und per-user sieve scripts at the same time

Hi list, I'm trying to get a global sieve mailfilter with per-user sieve scripts to work. At the "lda"-section in the dovecot.conf file I have: global_script_path = /usr/local/etc/sieve/spam /usr/local/etc/sieve/spam: require "fileinto"; if header :contains ["Subject"] ["***Spam***"] { fileinto "Spam"; stop; } which will work fine delivering Spam Mails in a Spam dir for every user. If a user creates his own .dovecot.sieve file the global script will not work anymore. How can I enable global and local per-user sieve scripts at once? Is this possible? Do you know any workaround so all users will have the same (Spam-)sieve filters beside there own (global templates or so)? Matthias