silverstripe/silverstripe-framework — pull request #2680 by Firesphere (2013-11-24 13:02:37+00:00)
Title: ENHANCEMENT Recursive grouping in templates

To be able to use the children of a grouped list in templates.

Example:
<% loop MyGroup.GroupedBy('Country') %>
$CountryName
<% loop Children.GroupedBy('City') %>
$CityName
<% end_loop %>
<% end_loop %>