The price quote/invoice from the vendor details the total price for payment. Can we complete a single SF-182 with attached class roster or make each student from different sections fill out a form with a prorated amount?
Assuming that there is a single vendor, a single organization receiving the training, a single training officer that tracks the attendees overall training status, it's the same training at same time, and there will be a single line of accounting that the training session will be charged to, then there should be no problem with providing a single SF-182 annotated that there is a class roster attached.
However, if the members have different training officers, then you might need to make a form for each of them. Since this is for US Army training, they state, "This form is used by the United States Office of Personnel Management and federal agencies. A Standard Form 182 is known as an Authorization, Agreement, and Certification of Training form. This form will be used to keep a record of various training activities an employee has completed. It can be used to ensure an employee meets the current qualifications needed to carry out their job duties and hold the employment position."
It's best that you contact the cognizant training personnel for your/their organization(s) to make sure you are able to meet their need to track the training being provided.