Combine Group Title using a FIELD => ID + numeric indicator {#}

Hello Ahn!

I would like to ask if it is possible, for GROUP_TITLE to make a combination between:

'group_title' => array( 'field' => 'title' )
and
'group_title' => '{#}'

I have no idea how to mix both (or even if it is possible at the current moment). I would like to suggest some extra param to activate the number indicator on each GROUP_TITLE, TRUE or FALSE.

Something like:

array(
    'id'     => 'my-block',
    'type'   => 'group',
    'collapsible' => true,
    'group_title' => array( 'field' => 'title' ),
    'counter' => true, // Combines the title with the iterator {#}: Displays a number before the title (#1: My Title)
    'save_state' => true,
    'clone'  => true,
    'sort_clone' => true,
    'fields' => array( ...)
)

Nothing essential, but could be nice to have it someway.
Thanks!
G.