Multi-State Button Custom Styles Disabled

I have a multistate button with custom selected and unselected styles applied to each button. These styles have been defined using the custom style GUI (Buttons/MultiState/Duty1/Selected and Buttons/MultiState/UnSelected).

When I disable this multi-state button I would like the buttons to gray-out. I tried adding this to the stylesheet.

.psc-Buttons/MultiState/Duty1/Selected:disabled{
	background-color: var(--neutral-30);
	border-color: var(--neutral-30);
}

.psc-Buttons/MultiState/UnSelected:disabled{
	background-color: var(--neutral-30);
	border-color: var(--neutral-30);
}

But that doesn't seem to do anything.

I also looked at the built-in CSS files to see how the buttons handle enabled/disabled and saw

.ia_button--primary--disabled {
    background-color: var(--callToAction--disabled);
    border: var(--border--disabled);
    color: var(--neutral-30);
    cursor: not-allowed;
}

So I tried

.psc-Buttons/MultiState/Duty1/Selected--disabled{
	background-color: var(--neutral-30);
	border-color: var(--neutral-30);
}

.psc-Buttons/MultiState/UnSelected--disabled{
	background-color: var(--neutral-30);
	border-color: var(--neutral-30);
}

And that did not work (I didn't really expect it to)

I can create bindings based on the enabled property of the multistate button to change the style for the buttons, but I don't really want to do that for every multi-state button that I use.

Any way to do this with the CSS stylesheet?

So I guess that I'll have to go the "manual" route to swap the style based on the enabled state.