With the transferring witnesses and it is according to Rabi Elozor - בעדי מסירה ורבי אלעזר היא
Summary:
If there are two יב"ש, according to ר"מ they cannot divorce their wives unless there is a clear distinction between them mentioned in the גט, for we require מוכח מתוכו. The concern of ב' יב"ש is only by נפל and only if הוחזקו. The requirement that by ב' יב"ש they need to divorce in each other’s presence is because the ע"מ may not be aware that there are ב' יב"ש