Yes, I think so. One of my friend has applied four courses at one time for the whole year (four sessions). And she received the books of four courses one time by courier in order to save courier fee.
If two tests are taken at the same day, maybe you will take another course test after completion of the first one. It need physical strength for the long time of writing examination.
But just take time to study, not to hurry.
At the beginning, I can't believe I need to take 4 years for completion of CGA courses. In my schedule, I wanted to complete it in 2-3 years. Actually I did take so much time, due to failure of some courses, such as FA4, AT1 and TX1.
CGA usually does not allow the student to take two for high level course.
This is just a suggestion. You should consult the matter with CGA office.