Having two different appointment letters can create confusion for both the employee and the company, potentially leading to conflicts. Additionally, issuing two different appointment letters may raise questions about whether the employee will receive two different salaries, as an annexure of pay breakup would be attached, which is not only incorrect but also against the law.
To avoid such confusion, you can include points or clauses in the appointment letter clarifying the employee's role. For example, you could state, "The Company reserves the right to transfer your services to any of its offices and/or Group Company, either in India or abroad." This provision would allow the company to transfer the employee to a group company temporarily until a specific task is completed, enabling the employee to fulfill a dual role in both companies at the same cost.
Ultimately, the decision on how to utilize resources lies with the company management.
Best regards,
Elias