Pre-loading related contact lookups to a subform

Hello,

I'm trying to create a module to track group meetings and field data for each group member. Subforms appear to be a good fit for this but I don't want to add each contact every time manually. Can anyone suggest a good solution for this scenario?

Groups Module <> Membership Module (associating many contacts/members to a Group)

Groups Module <> Group Meeting Module (tracking individual group participation in every meeting)