Unlike Christianity and Islam, where homosexuality is more or less discouraged (now that's an euphemism!) it is no problem in Buddhism and idea of "gay Buddhist groups" sounds absurd to me. I have no idea!
The closest I can think of are fertility shrines, visited by women who want to become pregnant. The one in Bangkok (Tuptim shrine) was sanitized years ago (most of the wooden phallus removed), and there is one in Krabi (Tham Phra Nang, I haven't been). These are the only places I know where Buddhism and sexuality come together.
I didn't know about this temple, but will check and go next time I'm in Taipei.