In raw HTML you can group options in a drop down list using the <optgroup> tag. See https://developer.mozilla.org/en-US/docs/Web/HTML/Element/optgroup for details.
Can this be achieved with Composer's drop down list widget?
I've added the ability to do this for dropdown lists using generation time values for the 4.4 release. We will add support for runtime (ie scripted) values in a future release/sp
Thanks David :)
At the moment, no.
Please log a feature request, and we'll take a look at it.