This is the HPE recommended Combine option.

When HPE IDOL Server indexes very long texts, by default it breaks them into sections, and indexes them as individual documents. Each document has its own ID, but they all have the same document reference. This process stabilizes indexing and ensures that the most relevant section of a text returns when you query HPE IDOL Server (for example, rather than an entire book). However, if several sections match the query, each section returns as a result. A query can contain multiple results with the same document reference, which belong to the same text, for example, different pages of the same book. If you display each result with the Print action parameter set to AllSections, you see the same text every time.

You can prevent HPE IDOL Server from returning different sections of the same source text by adding Combine=Simple to the query. HPE IDOL Server displays only the section that has the highest conceptual similarity to the query (unless you add Print=AllSections to the query, in which case it displays the entire source text). If multiple sections have the same conceptual relevance, HPE IDOL Server returns the one with the lowest section number.

For example:

http://IDOLhost:port/action=Query&Text=The Moonstone&Combine=Simple

In this example, if several results derive from the same source text, HPE IDOL Server displays only the result that has the highest relevance to the query text.