[Emerald] starter system

Hey Guys, I started ROM-Hacking(Pokemon Emerald) recently and I wondered how the starter system works. I know there are tools I could use, but I want to give out my starters via multichoice. Is there a flag I have to set so the rival knows which pokemon he/she has to choose? And are there other important flags that I have to set when I want to give my starters out this way?

Thanks in advance,
PsIQpath.

I've moved this over to ROM Hacking Help for ya ~

Sure, you could use a flag or technically even a var (although these tend to be used more sparingly) to indicate which starter the player chose. The only other important flag to set would be 0x860 to activate the party menu.