Thanks you for the quick response and the ideas got workarounds.
(from Eric’s iPhone)
Each event control track corresponds to a single runtime EventInstance, so within the confines of the UE4 sequence editor you do need to have an event control track for each instance you’d like to spawn.
Thinking a little outside the box you could create another event for the sequence which is set to Persistent and then place the explosion event on a parameter layout in the new event and use the level sequence to set the parameter value such that it triggers the explosion. You could then trigger multiple explosions using the sequence by repeatedly changing the parameter value to re-trigger the event on the layout.
Taking it further you could put a scatterer instrument on the parameter layout with it’s spawn total set to 1 and add the explosion event to the scatterer instrument’s playlist. Then you gain the scatterer instrument’s polyphony limiting, distance scattering and the built in pitch and volume randomization.
The trade off for both these approaches is you can’t get any control over the parameters or volume of any of the explosion event instances from the UE4 sequence.