To illustrate this question, assume we have two Imperial Class Star Destroyers who were both shipped out of adjacent construction bays at Kuat Drive Yards on the same standard day, and are both manned by a new crew of clones freshly graduated from the same batch on Kamino. Both ships can be expected to perform as nearly identically as can be expected in every way possible.
Both capital ships are currently next to each other. They are both ready to jump to Endor, and a remote signal was emitted from Kuat Space Traffic Control to fire both ships' hyperspace engines at the same time. Given such conditions, can the two capital ships see each other while still in hyperspace?
Is it possible that the answer depends on this associated question: How fast is hyperspace travel?
Edit: It seems the answer is now official in the movies. In Ep VII TV Spot 7 (YouTube link), it can be seen that from the cockpit of an X-Wing in hyperspace, fellow X-Wings are visible to the eye. I guess that settles it as canon. It seems ships can synchronise jumps after all.