Hello,
You could use firewall to achieve this.
You would need to create firewall rules for each of the clients that would allow the access to the router, and then, at the very end, add a rule that would drop all inputs from all other clients Make sure you create the rule to allow your PC first, as then you would not be able to reach the router at all if you block the connections first, and the rule to block everyone should be at the very bottom of the rule table. The setup would look like this