Body odour

I have been going out with a lot of different people while they drink alcohol, and any type of alcohol. But I would often have one or 2 friends in a group of a bunch of people, and they would smells something like chemical. I cannot tell what that smell is like, because I only smell it when I’m out with certain person that are drinking. One night I called it out to an other friend, and she said that she didn’t smell it at all, but I was smelling it so strongly. I don’t understand how I could smell it so strongly, but not my other friends. And I’ve experienced groups of people starting drinking at the same time and the same stuff, but there’s often one out of the groups that would smell so strongly chemical.

Should I mention it to the friends that smells like that? I’m scared it is diseases they might have. But if it is normal, and it is only bothering my nose, I don’t want to say it because it is very delicate to tell a good friend how horrible they smell when they drink.

Please, if anyone as an idea where I could identify that smell to see if it is fitting what I’m smelling from my friends, I would really appreciate it! And also, if I should warn them.

Thank you