You can organize your events differently, that's probably the easiest.
Create you objects (In there own event)
Give them a variable called (INT Flip_Rotate = 0)
(Not sure when you say flip if you mean rotate 180 degree again or flip, but anyway should work regardless, so if I misunderstood you can probably fix It easy)
Every 1 second
For each Object
If Flip_Rotate = 0
Set Flip_Rotate = 1
Set Flip_rotate = 0
If you want them to do it individual so it depends on when they spawned, you should attach a Timer behaviour to the objects instead of using every 1 sec.