Bit puzzled by the question. The solution proposed by Javito will cause the second waypint to be activated 5 minutes after the group arrives at the second waypoint. If you really want to prevent the second waypoint from being actived until 5 minutes after the first waypoint has been activated then try:
First waypoint:
On Activation: FirstWPDone = true
Create a trigger:
Condition: FirstWPDone
On Acivation: SecondWPFree = true
Min, Max and Mid all = 300
Second waypoint
Condition: SecondWPFree
But this is a bit convoluted. Have you tried looking at using a Switch trigger? Or delaying the activation of the first WP?