How to pass a spring.config.additional-location context parameter to war deployed in websphere 8.5?

I have a spring-boot webapp.war which was developed and deployed to tomcat 8.5, which is configured using a tomcat context file like so:

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Parameter name="spring.config.additional-location"
           value="/path/to/additional-location-application.yml"
           />   

</Context>

I’d like to deploy this on an existing websphere 8.5 server, however I am having trouble understanding how I can provide this optional context parameter to the application.

There is a similar question here: https://stackoverflow.com/questions/19968783/how-to-define-context-parameters-in-the-websphere-config-instead-of-the-web-xml

However ideally, I don’t want to modify the original web.xml in the war file. It’s also possible to provide this parameter in the JVM options like -Dspring.config.additional-location=/path/to/additional-location-application.yml however the problem with doing it that way, is that it would affect all the spring boot applications deployed on the same server

Notes:
Suggestion to use environment parameters instead:
https://ibm.software.websphere.application-server.narkive.com/Rcr0kBuU/how-to-define-context-parameters-with-was