I have a user guide that I need two versions of; the only differences will be a few images and a few small sections need to be swapped out.

I would really like to have the majority of the content in one file, so that if in the future I need to change a large portion of the file I don't have to track down what needs to be changed twice (or more since I might add more versions later on).

Is there an easy solution to maintain multiple versions of the same file?

Currently, I moved two large sections (where all of these differences will be) from the main file to two other version specific files, and then whenever I need to change something I will updated in the main file, copy over the sections from one version file, save it as a new finished file and do the same for the other version.

Thanks for any help in advance.