You don't want to
Merge. Instead, you want to
Essentially, you will need to simply open one of the
projects, then begin importing topics from one into the other. Once
you have done that, you will then need to massage your TOC and
Index to reflect the new combined project.
Sorry, but there simply is no RoboHelp supplied mechanism
that does this.
i do something similar to this frequently
you can open the projects .hhc files copy the portions from
the outermost <ul> </ul> from each and add them to your
new project's hhc you then only need to import the topics and the
hhcs will sort the broken links out by adding an x to them.
Its also just as easy to add the projects by choosing the
"New Merged Project" icon from your TOC (be sure to add the merged
projects folder to your original projects publishing list)