The Right to Information (RTI) is an act of the Parliament of India which sets out the rules and procedures regarding citizens' right to information. It replaced the former Freedom of Information Act, 2002. Under the provisions of RTI Act, any citizen of India may request information from a "public authority" (a body of Government or "instrumentality of State") which is required to reply expeditiously or within thirty days.
Yes, you can file RTI to different offices of the same department.
First Appeal is the statutory remedy available to the RTI Applicant, when there is no response from the Public Information Officer within stipulated time limit or the decision of PIO is not satisfactory or the PIO offered / supplied incorrect / misleading information or demanded exorbitant further fee etc.
In case you have filed two RTI to two different offices/departments and have not received a response or have received an unsatisfactory response, you can file First Appeal.