Meditation in the Church I was raised into was done in groups, but you also did it at home alone as well. I was told you need tranquility to start, but you should eventually be able to meditate sucessfully next to a jackhammer. I think I could only pull that off if the jackhammer was 1. off, and 2. there wasn't anyone around who was going to turn it on.
This wasn't mindfullness meditation, I'm learning that now from my therapist, it's a secular version the psychiactric community has been working with as a great alternative to medication.
That of course is sort of done as needed, alone if you happen to be alone when you say start having an anxiety attack, or in a crowded place if it happens there.
I dont see any reason you can't learn any any type of meditation, Samadhi, Kundalani, Zen, Mindfullness, or any other, from books or youtube.