From your question I understand that you need only the contains part of the query. Also I understand its too late to answer but anyone who is referring to this question might find it useful.
The query mentioned in the question can be used as below:
/sitecore/#media library#/#cgroups#/20180921/*[@@name = '%analysis-update%' or @@name = '%efficiency-update%' or @@name = '%work-update%']
Hope this is helpful.