Callback function in the action code gets excuted AFTER all subsequent workflows

Hi all, I am building a plugin that has a function with a callback function like so:

function(properties, context) {
  request_pay({
    //...
  }, function(rsp) {
    //callback code
  });
}

And this action is the first one that runs in a series of workflows.
I want the callback function to be executed before all subsequent actions,
but this callback gets executed AFTER them. (which makes all other actions useless)
I can’t use ‘pause’ action because it can take up to 3 minutes depending on users.

I assume it’s similar to this post:
http://forum.bubble.io/t/problem-with-sequence-of-actions-in-a-workflow/10289/6

I want this action to process completely before running the next action. Any ideas?