Hello,
Unfortunately, in the current version of ONLYOFFICE it is not possible to link Project Documents to another cloud accounts.
Thank you for your suggestion!
We will definitely forward it to our development team for further consideration.
If you have any more ideas on the improvement of ONLYOFFICE platform, you are always welcome to share them with us.
Any feedback you might want to provide will be useful for us. We invite you to post your idea on our feedback page:
http://feedback.onlyoffice.com/