These are two things. As Al correctly pointed out, it is better to keep a single instance of the workshop and just link to it from the other sections. Alternatively, you may need to manually move the workshop from week to week.
Workshop does support iterative / repeated peer-assessment - kind of. You can switch the phase to the assessment one repeatedly as needed. Each iteration can even have different grading strategy selected. For example, you can gather initial feedback via the Comments grading strategy for the first round, let authors submit new versions of submission based on the feedback, and then assess it again with more formal accumulative or rubric strategy. It is an advance feature though and is recommended for teachers familiar with the Workshop workflow and features.