I have an 'events' post type. I have another category called 'Speakers' and it has posts which are speakers.
When creating an event I need to select the speakers for each event through backend. I need to give an interface so that the admin could select the speakers for the event.
I recommend using the AdvancedCustomFields-Plugin. With this you can build a "relationship" between your post type 'events' and the 'speakers'. This way you can choose the 'speakers' on every 'event'.
The Plugin is well documented. See for yourself how it works: http://www.advancedcustomfields.com/resources/relationship/