To start a process in different appian environments

Hi all,

I have a use case where we want to start a process (process model independent of parent process) in different Appian environments from its parent process model.

So we need to accomplish an action in appian environment 1 and appian environment 2 once certain actions are completed in appian environment 3.

PM in appian environment 3 should trigger PMs in Appian environment 1 & 2 upon its completion, we cannot use web API or integration here.

So I wanted to understand if we can make use of 'start process by email' option to start multiple process which are in different appian environments.

Also if we have any other better approach for this scenarios? Any suggestion here much appreciated.

Thanks,

Preji