DB49,
good and helpful amswer.
The business requriement is really that Sales for invoice reasons need the delivery group populated but for planning it causes a problem as certain items can be despatched legitimately early.
Yout idea about using the Fixed-date-quantity flag is a good one although when I tested placing a Delivery group '1' in the items then still still rescheduled my first item in line with the other.
May be I have misinterpreted but I thought you were saying it would not do that and honour the fix date requirement tick.
thanks