groups

The root element of a layout-group publication resource. It contains a sequence of group elements defining all the groups that are to be available for a publication's section pages. It may also contain a sequence of content-type-group elements referring to a list of existing content-type names, which can be used by the allow-content-types element of an area of a group.

Syntax
<groups>
  <group>...</group>+
  <content-type-group>...</content-type-group>*
</groups>