When a character is blinded, they suffer the following drawbacks:
A blinded creature can’t see and automatically fails any ability check that requires sight. Attack rolls against the creature have advantage, and the creature’s Attack rolls have disadvantage.
Given that these seem to be the only restrictions you have while blinded, would it be possible to determine an individual creature's location and identity (to ensure you're not attacking your allies) by using your other senses? This question also applies to combat in a heavily obscured environment. I can't seem to find any concrete rules about this type of situation.
Best Answer
Yes, you can.
Using the following rule which should also apply when you are Blinded (PHB p. 194):
Additionally, other characters can perform a Help action to give you advantage in your turn, which would offset the disadvantage above. This could be regarded as shouting directions to you, maneuvering a creature towards you, etc.
Also, characters have what are essentially Free actions (Other Activity on Your Turn, PHB 190) on their turns, which can include speaking a few words. A DM could rule that calls of 'Foe to your left,' 'Two ten feet in front,' or 'I'm right behind you,' would help a Blinded character avoid friends and only attack enemies, albeit still with disadvantage unless given Help. Otherwise, they should have some chance of striking a friendly target, especially if everyone is clustered together in a wild melee.