I have exactly the same problem. There are apps which are able do handle multiple adressbooks.
would be great if also davdroid could handle this.
Add feature to display task/todo list deadlines in calendar
Task/todo lists are correctly recognized in DavDroid. It’d be great if they could be exposed to the Android/Cyanogenmod calendar in order to allow displaying of deadlines in the calendar.
aCalDAVdoes this and it’s quite useful.
I’m using 1.3.1-ose on Cyanogenmod 13.
Thanks for your suggestion. This would be within the scope of the OpenTasks provider (and not DAVdroid), please follow up there.
FYI: aCalendar+ does this, using OpenTasks storage backend. (Not open source though.)