The bicycle tour

You are right, this is correct.

The other road users see your two units in the same way - as they would if you were only one big group. If they come towards the bicyclists, they will see you from the front side. Independent from which group they see first, they will always see your front lights. On the same principle, they always see your tail lights when coming from behind.

Two separated units of bicycles

This observation directly applies to the model of the elementary magnets. The imagined “mini-magnets“ keep their alignment, no matter whether the magnet is whole or whether only a fragment of it is observed. To solve this task, think about what kind of polarity the elementary magnets cause in the fragments.