Add alternative name in master

xsocs/io/XsocsH5.py

@@ -362,9 +362,18 @@ class XsocsH5Writer(XsocsH5):
 
 class XsocsH5MasterWriter(XsocsH5Writer):
 
-    def add_entry_file(self, entry, entry_file):
+    def add_entry_file(self, entry, entry_file, master_entry=None):
+        """Add an external link to an entry in a sub-file
+
+        :param str entry: Name of the entry in the sub-file
+        :param str entry_file: Name of the file the entry belongs to
+        :param str master_entry: Optional alternative entry name in master file
+        """
+        if master_entry is None:
+            master_entry = entry
+
         with self._get_file() as h5_file:
-            h5_file[entry] = _h5py.ExternalLink(entry_file, entry)
+            h5_file[master_entry] = _h5py.ExternalLink(entry_file, entry)
 
 
 if __name__ == '__main__':