computer-go: Group understanding..

["Guillem Barnolas" <guillembar@xxxxxxxxxxx>]

    Hi!.. It's the first time I write here. I haven't written a go program
yet, but I hope to do it soon. Thinking about how to do it, a few questions
arose. Maybe you find them quite simple, I beg for your pardon in advance.
The first one is about groups. What do you consider a group ?.. I mean, if I
have a position like this one:

#OO####
O#O####
OO#####
########

Being it in the top left corner. This stones are alive, but I don't know if
a program should consider them one group or two groups that are alive. I
think I can't consider it a group because the stones are not connected, but
then It's quite more difficult to consider it being two living groups. And
then, If it's two groups, how do I know if they're alive?, because they
share liberties that happen to be alive ?.. I don't get it. It seems
difficult to code.

Thanks, Guillem.