You'd have to indicate what the logic would be behind the selection. Those who's due date is closest? Those who've had little or no training? Those who have some sort of priority due to impending projects or tasks? What about those who have no vacation scheduled during the training session or might be on some sort of leave at that future time? Would you prioritize those who have not had the training over those who might be getting a recertification?
Not so cut and dried maybe? Or is it as simple as only setting a percentage target and randomly choosing from a department until you approach the max percentage? If that were the case, you'd have to decide on how to address .5 employees. Round up or down?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.