Double-click to select units of same type?

Don't know if this is on the backlog, but I'd love to be able to double-click a unit and select all units of its type on screen.

I realize this gets a little complicated with battle groups, since you probably don't want to accidentally select assigned with unassigned units and screw up formations and whatnot. Perhaps a key modifier could control whether that can happen.

But for units at a rally point (especially where air units are thrown in the mix) I'm finding it difficult to separate out the unit type I want and send them to a particular spot. Maybe there's a mechanic in the game for doing this that I don't know about, but by convention in most RTS games I've played, a double-click does this.