Need option to append the values in Insight custom-fields through manual triggers in automation rules using A4J

One of the useful options when using automation rules is to retain the values in the Insight custom-fields while appending the new values as required.

Currently we have the option to retain the custom-field values and append new ones for normal custom-fields (Jira specific). This can be achieved using 'Copy From Issue' option in the automation rules using 'Manual Trigger'.

However, this option is not available for Insight custom-fields through manual triggers in automation rules using A4J. Using advanced option we can set the new values which will be eventually wipe out the existing old values.

So there is a functional requirement to retain old values and append new ones in A4J rules as required.