How to stop alternative gmail ID contact synchronization

You can follow the following steps and try
1. Open the "Contacts" app
2, Click on the menu option in the top right.
3, Then click "Accounts".
4. Then click on "Google". On some phones instead of giving Google, all the emails addresses synchronised will appear
5. Then Choose the account you want to unsynchronise.
6. Untick the checkbox next to "Contacts".
Once you do this. Automatically synchronisation will stop.
Restart the phone after this. Already saved contacts if any are there you have to delete such contacts once.

Here are the steps;
Open the settings app
Navigate to Accounts and tap on it
The list of all accounts synced on the device will appear, select the account you want to unsync and tap on it. Tap on Sync Account, and it will show you a dropdown of all the google features synced on the account. Scroll downwards to Gmail and toggle it off.

You can go to your mail and then go to the settings and select general settings. In that screen your email account will be shown. If you have more number of accounts all will be displayed there.
Now you will find a selector for sync on and off just above the email address.
This is to be kept off and then the contacts will be stopped showing in other email.
Another thing is that if some contacts are already there then that are to be deleted manually.