When you integrate Trellix IPS and Trellix Intelligent Sandbox, both the Manager and Sensor communicate with the Intelligent Sandbox separately. You have to configure the Intelligent Sandbox details for all the required Sensors and then enable the integration.
If you want to configure multiple Sensors with the same Intelligent Sandbox, you can specify the details at the admin domain and inherit the settings at the Sensor level. This saves you the trouble of having to configure the same details multiple times. If required, you can also customize the inherited settings for the required Sensors.