@mateusvitor
It seems that flushing by field group should be helpful and feasible. If there is a field group ID than all the data with that ID could be deleted.
Data is stored in the postmeta table. This data is associated with the post ID of the post the data is assocaited with. There is nothing in the way that WP is build to also to associate this content with the field group the field belongs to.
The number of queries that would be involve to track down and delete all data when a field is deleted would in all likelihood time out the process. I’m sure that the reason that a solution has not been is not because the developer does not want to provide a solution but because there isn’t a practical way to supply that solution working within the way that WP and the DB are built.
