Assigning roles to non-members?

Hello world,
We have a couple of non-member guests that I'd like to assign to roles in our agenda but they don't show up in the drop-down list of names. How do I enable non-members to be listed there for selection to agenda roles?

4617.toastmastersclubs.org/

Thanks!
Brian

Yep, since clubs started meeting online we have a lot of that, too. What we did was we added a member whose name is "A Guest" on the membership management module. A Guest has no email. We use the Toastmasters Logo as the photo. That profile is not made public. Now we have a "member" that we can assign a role to. We add the guest(s) name in the agenda notes so we don't forget who they are and how to contact them.