It depends on what EC activity we are talking about.
If your SGA group did something for the community, then it could count as community service. For instance, we student ambassadors in my college banded together at one time, painted some ceiling tiles and donated them to the children's ward at a local hospital. They liked it so much and even asked for more. I listed that as community service in my AMCAS.
But if your SGA group got together to have a couple of beers on a Friday night, then no, sorry, that is not community service.
Get it now?