This was a past situation. There was a presentation that only allowed one employee to present. Two of my employees, employees A and B, really wanted to do the presentation. Due to the time-frame and nature of the company, it was near certain that there would not be an opportunity like this again, so I couldn't say "Employee A this time, B next time". The employees were already not on great terms with each other due to personal differences outside of the workplace.
Although Employee B thought she was equally qualified, Employee A was more qualified for this task, so I would rather her do it. How could I have let Employee A do the presentation without hurting Employee B's feelings, especially given the already tense relationship between the two?