My first question is about linking from the Master project to the child projects in Robohelp 2017:
I've merged 3 projects into 1 project. In the welcome page of the master project, I try to add links to the starting page of each project, but I don't get the link to work. I did Insert hyperlink > Link to and then selected File. I then get the message that an external link will be created, and indeed the link doesn't work. How can I create an internal link?
My second question is about filtering. Is there a way to exclude child projects from the search results?
First I'd like to clarify what you mean by I've merged 3 projects into 1 project.Have you created a proper merge by referencing the child projects in the TOC of the master? Unless you have, that is not a proper merge.
If you have, then if you have structured the hierarchy of the source projects correctly, you will get a warning but the link will work. What do I mean by "structured the hierarchy of the source projects correctly"? Take a look at the Merged Help pages on my site.
The only way you can exclude child projects from the search results would be to not use RoboHelp's own search and replace it with Zoomsearch. How is described on my site. See Zoomsearch in RoboHelp but it requires some messing about for responsive help. Users could exclude a child project if you set up Dynamic Filtering to do that.