Portfolio Viewing Mode is included in PLUS account as well as PRO account.
Switch any pano of yours to Portfolio Viewing mode and only your panoramas will be visible as arrows to nearby panoramas.
To activate a Portfolio Viewing mode, go to the list of your published panoramas and click on the Portfolio View button.
When you click on any nearby panorama arrow when this mode is activated a new panorama will be shown with the portfolio view mode activated as well.
This special view does not apply to embedding (yet...)
Share this view with others to show your portfolio in a new way.