How can I CS after laning phase when team is constantly wanting to group

I've played 2 ranked games so far, did pretty decent in both of them won a game and lost one. My question is, every time laning phase is over I can BARELY CS without my team always wanting to group or the enemy team will group up to push towers it's very hard for me to CS. I feel like I could be a pretty good player if my CS wasn't terrible. So what could I do to CS after laning phase is done