Customization on "a new team member was enrolled" notifications/messages

I'd like to be able to customize these messages - ideally with HTML, but even if we could just update the copy, it would make a huge difference.

For us, we have different account types (e.g. some people are Associates that are earning commissions and some people are just customers making purchases from those associates that don't earn commissions). Right now, an upline is notified when a new team member is enrolled, but that notification doesn't tell them what type of account the new enrollee is... and a new Associate is cause for much more celebration than a new Customer account. Hence, I'd love to be able to tailor that message - or just have the standard message configured to reflect the type of account.