Saving the refugees involves restarting that battle several times.
Basically, ALL your movements must be perfect, and it takes some trial and error in the beginning. Haivng a memory cart, so you can have multiple saves helps a lot too.
I can't give details, but you need to get Dantares, Symbios, Julian and Obright to the other side of the track and hit the switch. All characters needs to go straight against the enemies there (it takes a bit of luck here too, since sometimes the knights will choose to attack the refugees instead of your guys. A good trick is to try to get Julian the closest as possible to the enemies. Since he's a "hero", the enemies will attack him with maximum priority.
Take care of leveling up a bit, since the enemies between tracks can kick Julian's arse if he's not strong enough.
As the refugees, you need to move them in an almost exact path. Some of them have a shorter movement range than others, and you need to take that in account. Also, their leader has a healing herb and 13 HP, so he can survive two hits. I never managed to save them all without getting him attacked. So try to use him as a shield for the other refugees.
Also, you *need* to get all refugees to cross the track, otherwise, the ones that don't *will* die.