My DS was mostly EBM fed for the first 6 weeks or so because he kept falling asleep. We simply dropped one top-up at a time. And were prepared to have to move the feeds closer together.
Don't immediately drop all the topups - bub needs to get used to the hard work of sucking from you a bit more gradually. Start by dropping whichever one is at the quietest time for your other girls. Then a few days later drop another.
How often is she feeding at the moment?
And you may need to be very mean to keep her awake - we used cold face-washers, bad singing, and drops of cold water. This may be an excellent job for your older girls!

Another option (but it can be a bit fiddly) is to use a supply line. That way she's not having the bottle directly any more, and is getting more nipple-sucking practise.