[syslog-ng]question about filter option host()

Does this directive match the entire hostname? I have a router called 'mem' with a filter setup to log it in my routers directory. I also have a few switches called 'memsw1', 'memsw2', so on, so forth. I have a filter logging them to my switches directory. However, I now also have a log file for each of the mem* switches in my routers directory. Is this normal behaviour or do I possibly have a config error somewhere? Thanks, David Monk CCNA, MCSE david@purplebear.net