Is your requirement to always wait for a minute before kicking off the second adapter service? If so, you can create a simple java service modeled after the sample.threads.utils.stall java service located in WmSamples. This will force a sleep of n seconds after adapter service A completes.
If, on the other hand, you want to wait UP TO one minute after invoking adapter service A, before kicking off adapter service B, then you’ll need to create a java service that uses the Service.doThreadedInvoke() API method to invoke a Flow or java service on its own thread.
When the service that is invoked completes, it needs to return its results using pub.sync:notify using a key that you pass to it. I prefer to wrap pub.sync:notify with my own java service in order to provide a means of returning exception info from a service invoked on a separate thread.
Your calling service calls your doThreadedInvoke service to kick of adapter service a, then invokes pub.sync:wait with a wait time of n seconds. If the wait time expires before adapter service A returns results, your pub.sync:wait will throw an exception. You can wrap this in a try-catch structure so that your catch behavior can be changed to not throw an exception, but simply to continue processing with adapter service B.
See this post for additional comments on exception handling in service invoked using doThreadedInvoke.