Think you speak about calendars stored to servers like
http://icalx.com/.
With those you store all your events/todos with one file. So you can only retrieve those with "downloading" that one file.
Reminderfox can use those services with your local events/todos and offers two methodes:
1. Use as store location: your events/todos are send/received to that server and will be shown in Reminderfox as the "main" data.
2. Subscribe to remote location: here we download the remote data file and handle it as a separate "List". That data can not be loaded to the "main" data directly, but you can move/copy individual events/todos to that "main" data. That would show -- as you requested -- all in one list. BUT for those moved/copied items you loose the connection to the remote server!
An alternative way to handle local/remote storage (Subscriptions and User Lists)In the process to implement CalDAV the Reminderfox Team also discussed to reduce Reminderfox to just two lists: one for events and a second for todos/tasks. All "subscription" data or User Lists would be stored to events and todos respectively
With that proposal User Lists -- individual collections of tasks -- would be converted into the "Todos" with an CATEGORY attribute like we used it with the User List. That way individual collections of todos/tasks could be selectively show with filtering or Views.
Would be interesting how such an approach meets the requirements of the ReminderFox users!?
Feedback welcomed!Reminderfox Team
Günter