Inspired by following 2 questions:
When eating a Shabbos Seudah how much must the ones that are being yotzee from the Bal Bayis in lechem mishneh and the bracha of ha'motzei eat from the challas themselves? Must they eat a cazayis of the lechem mishneh then may eat from whatever other bread they want (that wasn't part of the lechem mishneh) or may they eat even a little bit from the lechem mishneh and the rest from other bread? I have heard in the past their is a maklokes in this. Please post sources.