Require administrator approval for only registrants completing alternative form?

I've created an alternate registration form tied to a special role on my website, and I would like to require only those registrants completing this form to wait for administrator approval before they're allowed to login. My standard form is set to allow new registrants to login without administrator approval, and I would like to keep that functionality as it is.

I've found how to show the "Waiting for Approval" user queue regardless of the site registration requires activation setting, but I can't determine what dictates how a user appears there. I've created several test accounts, and only a couple of them are showing there. Can someone provide some insight on how to get registrants of an alternate form to appear in that queue?

Thanks!