1-2-3-4-5 reps or 1-2-3-4-5-4-3-2-1 reps of :
devils presses @ 22,5 / 15 kg (scale the weight if need to)
1 works at the time, everyone does same amount of reps.
I do 1 rep, you do 1 rep and then 3rd person does 1 rep, next round everyone do 2reps , then next round 3 reps and so on.