Could I use difference `MONGO_OPLOG_URL` on the same hosting?

deployment
1

I use MUP to deploy my app.
I have one hosting, but deploy 2 app with the same mongo docker container (2 databases name)

// App-1
....
env: {
      ROOT_URL: 'http://1.2.3.4:5555',
      MONGO_URL: 'mongodb://mongodb/foo',
      MONGO_OPLOG_URL: 'mongodb://mongodb/local-foo',
      PORT: 5555,
    },
-----------------
// App-1
....
env: {
      ROOT_URL: 'http://1.2.3.4:6666',
      MONGO_URL: 'mongodb://mongodb/bar',
      MONGO_OPLOG_URL: 'mongodb://mongodb/local-bar',
      PORT: 6666,
    },

Which difference if I use the same MONGO_OPLOG_URL?