Back in the day, in my chapter, often a woman receiving a COB would already have a friend or two in the chapter. If so, the friend(s) would find her and offer her the bid in person. Otherwise, the president or another officer would do so. We would usually COB one or two women at a time.
If you are looking at COB'ing 19 women, you could invite them to your house or some other location for a "pref party", and then surprise them with bids. For those who accept, the pref party turns into a bid day party.
