Why is "chère famille" not acceptable? I would like to open a letter with "Dear Smith family." If "Chère famille Smith" is not acceptable, what then would I use? "Chers tous" just sounds a bit too generic.Well, you can say:
but you can't say "Chère famille", for a collective noun, we use "Chers tous".
I can't see any way to say hello to both a given member of the family and the rest of it at the same time.