Bloom (standard asset) not reacting to alpha channel?

I want to selectively apply bloom to certain objects, and from googling I've found that the only way to do this is by changing the alpha channel of the albedo RGBA of the material. This doesn't work however, and I'm wondering if there is another way to go about this?

The problem here is bright floors getting overexposured. I still want to keep specularity, so toggling it off is not an option.

Thanks in advance!