Although it's not required, it's pretty common to break up the dayparts in a script into broad source group categories "Broadcast", "Cable" and "Syndication".  The "Group" definition makes it easy to define a daypart that has only one category of sources.  Just click the group you want:

 

 

 

 

In this example, everything that you indent under this "Broadcast" heading will make available only networks, programs and genres carried on broadcast networks.