Does my Phal have a fungus??

[Justine]

Hey everyone! So, one of my Phals has recently taken a turn for the worse, or so it seems. It has developed these little brownish/black spots on all the blooms, and two of the leaves turned yellow with brownish spots before finally falling off. The remaining leaves are doing ok, but seem to be turning a bit yellowish. I have attached a picture of the blooms with spots... what do you all think this is?? Is it a fungus? Or is it nothing at all? And if it's something, how should I fix the problem?

If this is definitely a problem, do you think it's worth separating this plant from my other Phals? I have them all sitting together and the other plants look healthy for now. I just don't want to do them any harm by accident.

Any feedback you might have would be appreciated!!!