Unlinking associated Imported clips?

Hi all,

I've been creating a long sequence shot in 5 - 10 minute sections using two cameras. I've edited 4 sections but now, on the 5th, whenever I try to import the main footage clip and then the overhead footage clip, put them on separate tracks and synch them, they both snap to the start point and associate (with the orange selection outline and connector). I can't un-associate them and it's causing major problems for me... does anyone know how to turn the associating feature off please? Working with Ru v1.5 on PC.

Thank you!