Beautiful Jade bush. Good score and you got it home in one piece.
Do not even consider separating them for that would destroy the symmetry.
Yes it does need more sun.
A little pruning at a time is a good idea.
When they grow big like this, jades tend to prune themselves.
The branches become top (end) heavy and just break off.
Usually that is lower down than you would cut it, so the shape changes drastically.
It is best if you control the pruning.
Cut a few of the extended (longer) branches shorter.
Let them grow and bush out and then cut a few more, randomly spaced around the plant.
Prune large jades every few months during growing season and they will stay happy.
My mother plant 20+ years old is now 6 feet tall and has a trunk 9 inches in diameter.
Well that was true last week, but I waited too long to prune it and now it is only 2 feet tall.
The top 3 feet broke off and by the time I was finished with reshaping it I have a skeleton.
I knew better, but was too busy with other things.
All the advice above is good, especially the re-potting. It looks happy in the present pot and unless it is root bound, I would leave it alone. Do not add more soil to the top. That can sometimes be disastrous. In some cases it can cause rot at the base of the plant.
