Expansion after a dash

I'd like to be able to insert an Instant Text entry right after a dash.

I'm working on depositions, and instead of hitting "enter" at the end of a sentence, I have to move down two lines to the next entry in a Q:/A: template like this.

Pages and pages of...

Q:

A:

So I made an instant test "zx" of [nospacing][down][down][end] to move to the next entry instead of moving my hands away from the letter keys as I type. Big time saver.

The only problem is that when one person interrupts another, instead of putting a comma or a period, I have to type a double dash.

Q: So when did you--

A: I told you already.

When I type a double dash, like that, entries will not expand. So I cannot type --zx and have "zx" move my cursor down to the A: where I keep typing.

So is there any way to add a dash to the characters after which IT entries will immediately expand (as it does with periods and question marks)?

(It could also come in handy for IT entries placed after non- and un- and pseudo- and all the other hyphenated prefixes.)