I would like to make sure which answer to this question is correct.
Change this sentence to a shorter version by using direct and indirect object pronouns.
Q : José les tira las serpentinas a ellos.
A1: José ses las tira. OR
A2: José se las tira.
1 Answer
From here:
le -> se Change
Indirect object pronouns "le" and "les" are changed to "se" when followed by "lo," "la," "los," or "las" to make pronunciation a lot easier.
So your option A2 is the correct one- both le and les become se, never ses.