Depends on what you want from them.
Yes, you could ask both for help or support in any manner. But I would ask only one of them at a time to build a connection with you.
I tested the method from @Samurai yesterday. Put all items with fields etc. away. Listened only once to alien intercession and ask them to establish a connection. Waited over 2 hours before I listened to anything again. Felt like they were building a lot of new connections in my right hemisphere. Gonna write more about my experience later.
@Nabs101 wrote in another post, that our energy body needs to:
acclimatize to their vibrational frequency
This probably means that listening to Angelic VIbrations (ver 2.0) will make connecting to angels easier! Dream wrote in the description:
This vibrates your entire body and being and entire energy system with the base vibration of an Angelic being (the same type as in the angelic intercession)
So listen to Angelic Vibrations a few times and then try Angelic Intercession!