Compare vector index and update it

if A=[300 499 599 866 886 1000] valores stored value

n1=[1 2 6 ] the position that n1 occupies in A. for exemple n1(1)=300, n1(2)=499 and n1(3)=1000

n2=[ 3 4 5] the position that n2 occupies in A. for exemple n1(1)=599, n1(2)=866 and n1(3)=886.

if n1(1)=0 and n2(1)=0 i wiil have n1=[2 6 ] n2=[ 4 5] and A(n1(1))=0 and A(n2(1) ) =0

A=[499 866 886 1000] .

How to update automatically the new position occupied by n1 and n2 in the new A?

With this example you can see that n1=[1 4 ] n2=[ 2 3].