Sometimes it would be very handy to limit the type of content for specific groups. Groups, that show their content on the main page, should f.ex. only contain web maps or web apps, whereas data groups should be feature service or map service only.
This idea has been merged with Allows Group owners to set a default type(s) of items (maps, apps, etc) that are visible to group end users..
This feature would help to keep a better structure of the group content!