I recall there was a spell which created a life link in previous editions, allowing us to take damage and share it with the group's players. Are there any similar spells in the 5th edition?
There is one - Warding Bond, a 2nd level spell available to all Clerics, and Paladins of the Oath of the Crown from Sword Coast Adventurer's Guide.
While the target is within 60 feet of you, it gains a +1 bonus to AC and saving throws, and it has resistance to all damage. Also, each time it takes damage, you take the same amount of damage.
Resistance to all damage means that effectively, the spell halves all damage an ally takes while causing you to take the same amount of damage - so it's the same as if half of the damage was dealt to each of you.
It's not a spell, but Oath of the Crown Paladins also get a class feature that enables them to take the damage dealt to a nearby ally themselves, substituting their hit points for the ally's.