Hi Andrea,
You could use the attribute assistant add-in.
Best,
Melanie S.
I know I'm a little late to the party on this thread, but I think the To_Junction_Field rule may work for you, so long as your data participates in a geometric network. This way, only the data from the downstream intersecting point would be transferred to the line. Depending on how much information you're looking to join, you may have to set up the rule several times, one for each field you wish to populate. Without the geometric network, however, this function will not work. Hope this helps!