Group fields

Hi,

it would be very nice to group fields in content types > manage fields tab.

Illustration:

Users can add/edit field groups. Fields could be attached to a group.

Groups should have the following properties:
Checkbox: "Required group"
Dropdown: "Number of values" (Maximum number of values users can add)

When creating a node (node/add/) users can add this group of fields as often as set in the group properties "number of values".

Illustration:

There is a module (field collection) that can group fields but it is circular and the user loses the clarity because its seperate from the content types > manage fields tab.

We need this in core! :)