Check forms - Ability to add another person as a sign off and keep the required sign off personnel having to sign off

We have multiple trainers for one aircraft type. Dependent on the type of training the Examiner would like the ability to add another person as a required sign off in some instances. If we use the Override Authorised Sign Off Personnel function by adding another person. If they sign off the Check form before the currently assigned required sign off personnel - the new sign off person counts as one of the mandatory sign offs and then one of the required sign off personnel doesn't have to sign it off. We want the ability to have the new person sign off plus the original required sign off personnel.