I've never tried to make that work, but I will say that getting units to die shouldn't be that hard. Just keep the city stocked with weak units and some strong defenders nearby. Only move in the strong defenders if your enemies threaten to capture the city (by having more attackers than you have sacrificial units).
Just be aware that as you are sacrificing all those units you will be feeding your opponents xp. Also, the flesh golems you get will be unable to get xp on their own and so will require you to sacrifice your own units with promotions if you want to improve them.