Group Membership- Criteria-based + Manually managed

Hi,

I'm configuring my first FIM implementation, and I need to have AD Group membership have criteria-based members as well as manually managed members. I am aware that this can't be done directly on the Group in the Portal, but is there another way? I read somewhere that a Group can reference Set members, but I am not clear about the syntax, or how to go about doing this.

Thanks for the help!

Rob