Evidence that Antifa is a multi-group organization:
-Logos, stickers, common slogans etc.
-The international anti-fascist defense fund.
"Any individual or group that donates an amount greater than $20U.S./€20/£15 will be invited to join the growing CREW OF PEOPLE all over the world that make the decisions about how The International Anti-Fascist Defence Fund is used."
Some other examples
-The non-profit, political organization Antifa Toronto. With 1800 members.
-https://antifainternational.tumblr.com/ - advertising meet ups and demonstrations.
-Antifa Checker on facebook with 2071 followers claims to be a nonprofit organization.
-Commonly used attire that identifies ANTIFA. Dressing in black, covering your face with a mask. Many piercings and tattoos..... haha kidding