Creating calendar sub group el capitan 10.11.4
I am trying to group my calendars into two categories - the first is my calendar, which lists different projects I work on, the other would be a group for another part of the department I support with a list of their projects. Is this possible? I basically want to group the list of calendars into two categories. It seems like this should be really simple and obvious. I have created a new group and am trying to drag the relevant calendars into the new group and that doesn't work. I have been looking online for ages and this doesn't seem to be a function, so posting on here is my final resort! Thank you in advance for comments and help
iMac, OS X El Capitan (10.11.4)