I think a Dragomira who has been maledomed would consider joining a harem.
		
		
	 
At her age, depending on exactly where she's from, Dragomira's human life would have occurred at a time when every other conquering warlord had a harem.
She would have spent a good couple centuries of her early vampire life in a world where every other warlord, king, czar, sultan and emperor had some version of a harem.
Once upon a time she was no more badass than Rachel. It's rather probable she's already been in a few harems at varying points through the centuries. Hell, maybe she even had a harem of her own once she was powerful enough to command one.
She comes from a time when it was perfectly normal and natural for a woman to submit to a powerful male, and just as normal and natural for a powerful male to have a harem. So yeah, if you already dommed her, she'd probably be cool with being in a harem, generally speaking.
The only real hiccup is once she becomes school headmistress, I assume she'd want to maintain some semblance of professionalism and wouldn't do that sort of thing with her student. It's one thing to fraternize with a student as a professor. It's a bit different...not much, but a bit...as headmistress if she takes the job seriously.
Then again, maybe she's just too old to care about silly things like 'appearances' anymore. lol