Webform: get field value from the Entity select option
I was able to get all three of the below tokens to pull the single first email address for the group node's field_email.

[webform_submission:values:groups:entity:field_email]
[webform_submission:values:groups:0:entity:field_email]
[webform_submission:values:groups:0:entity:field_email:value]

Only [webform_submission:values:groups] returns 'Node Title (NID)'.