Try this:
Create a Global variable called IsPaused
Create a Global variable called Timer
Create a family FamilyObjects
Put all objects you want paused into FamilyObjects
Timer=0
System > Timer (Is Greater than 0) > System > Set IsPaused to 0
System > Timer (is less than or = 0)>System > Set IsPaused to 1
System > IsPaused =0 > Set FamilyObject Time Scale = 1
System > IsPaused =1 > Set FamilyObject Time Scale = 0
-----(sub event---)------- > System > every 1 Second > System -1 > From Timer
On some Condition > System > Set Value Timer to 3
It actually may work without the Family and just trying it setting the System timescale to 0 and 1, if not, setting the time scale of the objects to 0 should do it.