Exchange 5.5 Spam Block multiple domain

I would like to block several known spam site from sending my NT4 SP6, Exchange 5.5 SP4 server.

I know in Exchange 5.5 on the Internet Mail Connector, the tab “Connections” with the “message filtering tab”. you can specify the address but you have to type each offending host one by one. Is there a way to import an ASCI text file with about 5000 offending site in my spam block list ?

Thanks,
Robin