As as SAFe practitioner, we use lean portfolio management techniques across more than 40 teams, rolling up programs at the Program Increment level on a quarterly basis. Our Epics and Features are created in User Story Maps (love this feature) well in advance of PI Planning, but when team starts PI planning, further elaboration takes place. This creates a mix of existing and new Epics, Features & Stories. Would be very helpful to be able to link to existing records, if they already exist. I have not found a way to link to existing record types.
Thank you for your idea. This is currently possible a couple different ways:
You can copy the URL to a record and paste it into a whiteboard
You can add multiple records to a whiteboard from a report by clicking the export icon, then choosing the option to Add to whiteboard as shapes (see screenshot.)