Question: how to make singular use same letter Z for integers? (same for _N)

the command singular can return results with _Z or _N as it says in help

The singular function may return expressions prefixed by _Z or _N, representing the integers and positive integers, respectively.
 

But it changes these letters by adding different number at the end for each call., Yet they all mean the same thing, which is an integer:

singular(1/sin(x),x)
                         {x = Pi*_Z1}

singular(x/sin(x),x)
                         {x = Pi*_Z2}

singular(x^2/sin(x),x)
                        {x = Pi*_Z3}

This makes it little hard when I try to make union of these results to only keep the unique singular points, since they are different symbols, yet they are really the same: integer times Pi.

Is there an option to tell Maple to use _Z for everything? And not keep adding new numbers each time it is called?

May be clear some internal memory table after each call?  Otherwise, I have to add more code to parse all these results and convert all _Znnn to just _Z  if it is there in each result, after each call is made.

Same issue for _N

Update

Additional example to try/test against

expr:=1/(sin(x)*cos(x)*tan(x));
s := singular(expr, x);

expr:=1/((x-1)*sin(x));
s := singular(expr, x);

expr:=1/(sin(x)*cos(x-Pi/3)*tan(x));
s := singular(expr, x);

In all the outputs above, I'd like to have same _Z show up. This will make it easier for postprocessing later on. Best solution will be to tell Maple itself not to change _Z if possible, otherwise one will need to add code to do this afterwords for all possible cases.