I know that there is a @index function that cycles through all the cameras. Is it possible to create other such groups, @outdoor for example that would consist of only the outdoor cameras?
In the properties of each camera you can add/remove groups. Once you have created a group, you can turn on/off the appearance of the @group cycle option. To do this, you need to find the dropdown box below your camera live views, select the desired group, then click the small gear icon to open the group's properties.