you can work in any company as a Lawyer subject to the condition of heir, and you may take responsibility to look after criminal cases or matter of company, subject to approval, so far. Generally in-house lawyers of company bound to look after any matter of company as assigned to them time and again by the company.
There is no such designation called criminal lawyer for the company, you may call it a criminal lawyer or civil lawyer as per your convenience.
If you are appointed as a legal adviser to the company you can appear before court on behalf of the company to the cases filed by the company or against the company.
You may choose to practice whichever side you wanted to an can inform your decision to the company appointed as their panel lawyer.
Be informed that if you are an employee on the rolls of the company even with the designation of company's legal officer or manager, you cannot practice law in the court of law being employed as a salaried person in the company.