how to use int identity as guid for merge publication?

Question

How do I set the nId column (from the example table creation code below) up as uniqueidentifier to prevent the merge publication wizard from creating an unneeded GUID column?

I am trying to set up merge publication in SQL Server Management Studio 2019.

My published tables use int and bigint identity for their primary key.

Here is an example creation script for one of my tables:

create table MySchema.MyTable 
(
    nId bigint identity(1,1) primary key,
    cName varchar(100)
);

However, when I use the "new publication" wizard, I come to this step where it says it will automatically create GUID column for published tables:

I do not think I should need this extra column, as merge publication assigns identity ranges for each publisher/subscriber, so there should never be a reason the nId can't serve as the uniqueidentifier, but I can't seem to figure out how to set the identity column as also the uniqueidentifier.