Newbie help with regular expression

Hi, I'm new to regular expression and would like some help/thoughts with 
the following questions.
I have a configuration file which looks a bit like this:

group = core
..............
.............
.............
...............

group = smsbox
............................
............................
...........................
...........................

My first question is :
 How do I correctly write a regular expression that will let me say give 
me the contents of the group = core ?
 I tried this \s*group\s*=\s*core\s*([^>]*)\s*group\s*=\s*smsbox\s* but 
that isn't really working as it would depend on group = smsbox being 
there. Is there
 a way around this ?

My second question is this:
  How can I extract  multiple identical groups  ( for example there are 
many 'group = smsbox' ) ? I would like to extract all the groups that 
match.

My apologies if  my questions aren't clear to anyone, I will clarify if 
I need to. Thank you.