I already have names and passwords set up in my own database. Yes you can.
Divide participants up into groups, so that each group of people is scheduled to the same session.
For example, set up one group for each class or category of people. Set these groups up in Security Manager. Use Security Manager to schedule these groups to the sessions you want. Because the whole group is scheduled, you do not need to change scheduling when participants change. Import these names into Security Manager from your browser, remembering to set the group that you want to import them into.