Reference two times the same node

Hello,

I would like to be able to reference two times or more the same node. I have a travel website, and I want to say to my customers that for example they will go first to Los Angeles, then San Francisco, and come back to Los Angeles. The default control in CCK reference doesn't let me try this, so I hacked "Node Reference Views Select", but it saves the city only the first time (so I will have only Los Angeles and then San Francisco).

I'm afraid I cannot doing it by hacking only "Node Reference Views Select", I think CCK Reference doesn't let you save two times the same node... But why ? And what could I modify to solve my problem ?

Thanks in advance