Yes, sole proprietorship and partnership business entities with more than a single employee are considered groups. They may be eligible to get group health insurance benefits if they fulfil the insurance criteria to qualify as a 'small business' in India.
As defined by the IRDAI, a group cannot be one that has been created just for the sake of getting group life insurance plans or group health insurance. So, if you and your spouse are running a family business with no other employees, you are not eligible to have group health insurance. However, if you have at least one more employee (family or not), you can avail group health benefits for all three people, depending on specific policy details.