The rules for maintaining concentration on spells after getting hit state that:
If you take damage from multiple sources, such as an arrow and a dragon’s breath, you make a separate saving throw for each source of damage.
This is an example for two very distinct sources of damage.
If a character who is concentrating on a spell gets hit by a creature with the multiattack feature, do they have to try to maintain concentration for each time they were hit? Or only one time, since technically all of the attacks came from the same source?