Is zakat obligatory on a shared flock of sheep that exceeds forty head, if the share of each individual partner does not reach the minimum threshold (nisab), and the sheep graze together?

The aforementioned sheep are subject to Zakat if a year has passed over them and they constitute a nisab (taxable amount), which is forty sheep. In this case, one sheep is to be given as Zakat until the number reaches one hundred and twenty-one, at which point two sheep become due. This applies even if the share of each partner, individually, does not reach the nisab.