A bit of a dirty trick which may or may not work would be to add a local/instanced variable to each apple "collided=0" and then have a collision change that value to 1 and make that trigger a pin command? I'm fairly new to construct so don't waste too much time on it if it doesn't work.
There probably is a more elegant solution out there though.
Alternatively you could make a new object spawn which is both bubble and apple together. Maybe.
-EDIT-
Ignore mine, the instance solution below is much better.