Both groups or single

The decision of single or both depends on many factors but the main factors are as follows

1. How many hours per day you will be able to allot for study. Appearently, if it's more than 6-7 hours then you both groups are recomondable.

2. Length of your study policy or methodology. For example if you prefer to make detailed notes instead of highlighting in books and making short notes, then it will take more time and in such situation single group is good option.

3. if you are going for classes then your policy and methodology will depend on the policy and methodology of classes. In such situation the decision should be taken accordingly.

So first think Properly and take decision.

At last do not say just 326. it's good total in first attempt.