Hi,
you need to insert one state prior spawning and in that early state, you will run everyframe a check against a variable or calling a method and checking the results.
for example if the variable is a bool, you get it everyframe and the next action in the same state use Bool check and will make you transit to the next state if the variable is true for example.
Don't use the FINISH transition for this, create your own event like "READY" and that's what you wikl call from within the bool check action.
if it's an int, use "Int compare", if it's a float use "Float compare" etc.
Bye,
Jean