Stuck -Advice, Tips and Strategy Ideas needed!

[Aqua Mage]

Hello =D
So anyway, I'm stuck on the part where you are in the Hills of Narshe after being re-united with your fellow team-mates. This is the part where you must stop Kefka's troops from getting to Banon and ultimately getting to the Esper. Also you are required to beat Kefka who is at the bottom of the hills guarded by two troops. Very Bahamut Lagoon-ish.

I've talked to friends of mine about this part and they have just laughed at me, saying it's very easy. Still, I'm finding it difficult.
So what I want to hear from you are any tips, strategy ideas or just plain advice.
e.g How to group my characters?
Should I attack Kefka before or after his incoming troops are destroyed?
Do you have ideas for a strategy I could use for Kefka?
Where should I have the groups set up to encounter the troops?

I'm greatful for any information you can give me. Thank you for your time.

PS: Just to help you, the characters who need to be grouped in the three groups are:
Terra, Locke, Cyan, Edgar, Sabin, Celes and Gau.