sendmail 8.10.x relaying

Hi list-users, is there a way how to make mail relaying username/password dependent and not host, domain or subnet dependent? Goal would be: 1. everybody can send mail to the MTA. 2. Only authenticated users with passwords can use the MTA for relaying mail from ANY host / domain / subnet etc. is there a way how to do it with sendmail? Thanx a lot. Philipp