Can the Droid Dispenser only dispense droids?

[Giftheck]

I'm considering how best to implement the Royal Guards, Death Troopers, Honor Guards and a few other unit types as 'hero support'. Now obviously heroes will not automatically call on these but I was wondering if the droid dispenser could be altered to dispense a playable unit instead of a droid.

[Led]

Napseeker used something like this to dispense playable units.  I think there was some discussion that might be found with a search.  (Single player only)