[CLEVERADA] a bit better will be `(grupo.length + 1) / 2`, as this will generate 62 + 62 + 1 for a 125 items group.
[CLEVERADA 2] depending on the latency and the "per item" time, `(grupo.length + 3) / 4` could still be better, it will do more requests but will process less emails.
------
Anyway, the complexity increase exceeds the (small) performance gain, so keep it as is. I just wanted to comment...