Related tasks
Create a BookXRefs file based on the xrefs in an existing Frame file
Set up a simple BookXRefs file (one group, three xref definitions)
Set up a more complex BookXRefs file (two groups, three xref definitions each)
Reference a common BookXRefs file
Delete specific xrefs from all files in a book
Rename specific xrefs in all files in a book
Replace specific xrefs in all files in a book
Related information
Using Special Characters

Set up a shared group that is included in two other groups

When you run the Import XRef Definitions command with this BookXRefs file, you will first be prompted to select an xref group. Based on the group selected, all of the files in the book will be updated with the three xrefs defined in that group plus the xrefs defined in the common section as defined by the "MERGE" sections. 
[General] 
AltBookXRefsFile= 
DeleteXRefCode= 
RenameXRefChar= 
ReplaceXRefChar= 
EditorType=0 
 
[Groups] 
Count=2 
1=MyCoolAppFull 
2=MyCoolAppLite 
 
[MyCoolAppFull] 
HeaderOnly=<$paratext> 
HeaderQuoted="<$paratext>" 
HeaderAndPage="<$paratext>" on page <$pagenum> 
 
[MyCoolAppFull:MERGE] 
Count=1 
1=CommonVars 
 
[MyCoolAppLite] 
HeaderOnly=<bold><$paratext><Default ¶ Font> 
HeaderQuoted=<bold>"<$paratext>"<Default ¶ Font> 
HeaderAndPage=<bold>"<$paratext>"<Default ¶ Font> on page <$pagenum> 
 
[MyCoolAppLite:MERGE] 
Count=1 
1=CommonXRefs 
 
[CommonXRefs] 
JustPage=<$pagenum> 
HeaderOnlyItalic=<italic><$paratext><Default ¶ Font>