Avoid page breaks between subdocuments using Writer?

I’d like to break chapters into multiple subdocuments without page breaks appearing between them on the ouput of the master document. Is this possible?

There is no reason for a page break between subdocuments unless you put one there (either at start of subdoc or manually between them).

If you want predictable and reliable formatting, I highly recommend working with a common template so that styles are consistent. What is your styling habit?

For more ad-hoc help, give more details on your present document structure, notably how you mark up chapter headings, sub-chapters, etc.