Control the visibility of custom fields based on User Groups

I would like to have the ability to be able to control the visibility of custom fields based on User Groups. This would, for example, allow us to greatly simplify registration for an event for any logged-in current members because their membership level status would be known. For example member discount prices could be given without requiring further validation fields (such as member number) which we are required to add in case they are registering for an event without logging in (or if someone else is registering for them).
Being able to hide the member number field (or other unnecessary fields) for logged-in members would enable us to give them a very good reason to login before registering!

Great idea.

I asked how to do this in the forums.

I'd like to see something like this implemented.

Thanks

Isn't each custom field has a setting called Access which allow you to control the visibility of each field base on access level already?

Tuan