Thank you for your post.
At this time, it is not possible to auto-play a Container field. Once a Container field is selected, the Actions window appears with one of the options being "Play". This cannot be selected automatically.
I recommend you enter this into the Feature Requests web form at:
The suggestions entered into this web form populate a database file that is monitored and read by Product Management and Development. Although I could copy your post and paste it into the web form, there are a couple of questions asked on the form that only you can answer.