Two cookie domains

[vi-afk]

Is it possible?

I am trying to make a express backend which is supposed to serve two js frontends, on different domains.
Only two, no wildcards.

Here is my config:

const cfg = {
  name: 'superSite',
  secret: sessionSecret,
  resave: false,
  saveUninitialized: false,
  rolling: true,
  unset: 'destroy',
  cookie: {
    secure: true,
    maxAge: 8*60*60*1000
    domain: 'supersite.org',
  },
};

then I initialize this as follows:

app.use(expressSession(cfg));
app.use(passport.initialize());
app.use(passport.session());

passport.use('local', new localStrategy({}, sessions.localStrategy.authenticate));

and then, method with passport.authenticate() sets cookie for supersite.org
How can I make passport js set cookie for megasite.org if request came from megasite.org?
Simply omitting 'cookie' field from configuration does not look good.
CORS is configured alright.