Conflicting clauses gifting a specific property in Will- Help

Can anyone point me to a legal authority or provide guidance on this point:

I have a Will gifting Property A to a son absolutely (the son is also the executor).

In a later clause in the will the said Property A is directed to be sold and the funds divided between a number of children including the son.

All of the persons to benefit from the sales proceeds if Property A is sold, have declined the gift and intends to do a Deed of Disclaimer (they are independently represented).

If the beneficiaries of the latter clause disclaimer the gift, how will the rule that the latter clause overrides the former affect the gift. Or does this rule even apply?