Resource group is to link up multiple sound file to play one after the other.
To modify or upload new Sounds to a resource group, go to Sounds in the telephony Menu.
Both creating new and editing will pop up a screen.
Select "Resource group".
Select an existing uploaded soundfile, create a new text to speech recording or upload a custom recording,
If you select Custom File as they type, you will see and the file option to upload a recording.
Voice: If you select Text to speech, you can select from 4 voice over artist.
Text: This will be where you would type in the message that will be played. You can press the speaker button on the right of the text field to preview the voice recording.