Multiple Enemies with Legendary Actions

Out of curiosity, has anyone here run a combat encounter with multiple foes with access to legendary actions? If so, how did you handle those actions? How did it affect the overall flow and balance of the combat encounter?

I have done this a few times, but generally try to avoid it unless absolutely necessary for the narrative element of combat.

In my experience, it bogs down encounters and makes players feel like the DM is constantly infringing on their turns (recognizing it is not technically on their turn, the psychological feel is that the player’s turn is being co-opted as the trigger for the multiple legendary actions). 

In this case, I would probably use one big monster with legendary actions, a secondary big monster without them, then transmit that second big monster’s legendary actions onto smaller creatures (exact same effects, but can be killed separately and act naturally on their own turn) or environmental effects or end of round (same effects, can’t be killed separately, occur independent of player turns).  Your end effect will be similar, but it will not have the same psychological feel bad to players. 

Quote from Sablemane >>

Out of curiosity, has anyone here run a combat encounter with multiple foes with access to legendary actions?

I have not done so yet, but it's certainly possible in the relatively near future. I suspect I will replace their legendary actions with other features that are less of a hassle to track (you can't just delete them, as legendary actions are a big part of their power budget).

This gets into a more general annoyance: it would be convenient if monsters had multiple versions depending on their role. It's entirely possible that a monster that I used as a big boss in tier 1 will be a minion in tier 3, but you don't want to use a minion-level writeup for a boss (boring) or a boss-level writeup for a minion (way too annoying to track). This is complicated to actually include in a rulebook, though (it becomes easier if you implement villain decay or the inverse ninja rule, because them you can just have a less powerful version, but I'd kind of prefer not to do that).

I have done it, but when I did I made a point to only use one Legendary action from one monster after each player turn. Otherwise it does bog down the combat and the players feel like they don't have any control over the combat. 

Thank you all for your feedback! I agree, if I were to do multiple legendary enemies, I'd still only use one legendary action per player turn or rework the enemies' legendary actions into timed events at various initiative counts or something.

I agree with Pantagruel666, it would be nice to have "scalable" monsters, but there really isn't any way to do this without homebrewing monsters entirely at this point in time. If there were a way to adjust monsters on the fly in DND Beyond that would be cool, like a slider that increases/decreases their CR, HP, Proficiency Score, and Ability Scores while keeping their basic skills and equipment the same.