Can you define an operator (***) in F#?

I'm working on Arrows in F# and I wanted to create a *** operator. I note, however, that (***), the necessary way to express an operator in a function definition, overlaps with the F# block comment syntax. So how could you actually express this?

I thought of maybe .***. but I think that will actually treat the dots as part of the operator, which I'd rather avoid.