For Classic TIBCO Administrator, in some cases the requirement  would be to set additional JVM args for specific application and not influence other application:
https://support.tibco.com/s/article/How-to-add-java-extended-properties-for-a-given-BE-Application-using-be-engine-xml

In TEA we cannot make changes in be-engine.tra file as this impacts all applications when you perform next deployment.

By default, BusinessEvents Enterprise Administrator agent uses the TRA file present under BE_HOME/bin on the machine for creating instance TRA files. But if you want to use a project specific TRA file to configure the instance TRA file and not influence other applications then ?

All

If you want to apply same functionality in TEA UI then you can specify a Master TRA file for that deployment.
The master TRA file is machine specific, thus, all the deployment in this machine uses this master TRA file only.

Procedure:

1) Select Applications deployment tab.
   The BusinessEvents Application Deployment page is displayed.

2) Click the More Options icon (3 dots) for the application deployment for which you want to apply a project specific master TRA file and select Master Application TRA file.
   See below:

   
   
3) Click Add New

4) Select Machine from dropdown list

5) Select Upload, if you want to upload a project specific TRA file to the host machine.

6) Alternatively, select Path and specify location of the TRA file in the host machine.
  ( Use this option if the master TRA file is already present in the host machine.)



7) Click Save.

After applying the master TRA file, status of all the existing instance changes to Needs Deployment, and any newly created instance uses this master TRA file.