Hello, it's already an existing option. Use meta criteria (white plus icon) to achieve it.

NOT condition is also available.

See this screenshot :

See https://github.com/glpi-project/glpi/pull/723

finished with tinymce update : https://github.com/glpi-project/glpi/pull/723

Tests needed to merge this PR

https://github.com/glpi-project/glpi/pull/708 merged

Currently implementing this suggestion.

See https://github.com/glpi-project/glpi/issues/159

Thanks for your proposal.

The task assignation to a group is a feature currently being developped.