Migrating to MyCloud - can I use old MyBook live as backup?

I have 2 MyBook Live devices one of which backs up the other overnight each night using Safepoint.  I am running out of space so am considering buying 2 MyClouds, splitting existing data across these two and changing the current MyBook live devives to act as backups for the 2 MyClouds.  Can I set up Safepoint on a MyCloud to backup to a MyBook Live or do I have to back up MyCloud to MyCloud and MyBook live to MyBook live?