Problem multiple collections per one portfolio

Hello guys and thank you for your help and congratulations to the community.
I would like to link one single portfolio to different collections.
So that I build the portfolio and then I flag all the collections available I wish to link. The problem is that as I select different collections, they do not show the single portfolio. The only collection working is the first one I have seleceted from the list of collections.
Look at this: http://www.tuscany-farmholiday.com/things-to-do/
The single portfolio can not appear in multiple collections.
Thank you so much, your help is much appreciated.