By my reckoning...
Group One - Between Notts, Warks, Durham and Essex. Durham and Notts play each other. Notts will qualify for division one if they avoid defeat. If Notts lose, it will come down to bonus points to decide who finishes higher between Notts and Durham. Warks will qualify for division one if they beat Worcs - and a draw will almost certainly be sufficient too. If Warks lose, they will likely finish behind Notts and Durham unless Notts beat Durham. Realistically, Essex need to beat Derby, hope that Worcs beat Warks, and hope that Durham don't beat Notts - although mathematically, they is a little bit of leeway there.
Warks have beaten Notts twice. Durham have beaten and drawn Warks. Notts have beaten and drawn Essex. The only match so far between Durham and Notts was a draw. So Warks will ideally want to qualify alongside Notts. Whereas if Durham can beat Notts, they won't be too fussed between Notts or Warks. Notts would ideally want Essex.
Group Two - Between Somerset, Gloucs, Hants and Surrey. Somerset will qualify if they avoid defeat. Surrey's only hope is to take 23 more points than Somerset, which is nigh-on impossible. And even then, Surrey would also probably need a winner between Gloucs and Hants. If there is winner between Gloucs and Hants, they will qualify and the loser will almost certainly be out (there's a tiny chance that Gloucs could still qualify if they are the loser). A draw would almost certainly put Gloucs through, and would leave Hants needing Somerset to lose - with it then coming down to bonus points between Hants, Somerset and Surrey for the second place.
Somerset will ideally want to qualify with Hants. Gloucs will ideally want to qualify with Somerset. Hants will ideally want to qualify with Gloucs.
Group Three - Yorks & Lancs have both already qualified for division one. But they play each other, which has relevance when looking towards the points they will each carry forward. The first match was a Lancs win.