how to collect from stream using multiple conditions

I'm trying to sort a list of Message object, this entity contain multiple attributs but only 4 are useful for us in this case :

• Integer : Ordre
• String : idOras
• Date : sentDate
• Integer : OrdreCalcule (a concatination of Ordre and sentDate "YYYYmmDDhhMMss" )

if this case, the conditions of selection are the following :

• if two Messages have the same Ordre :
  • if they have the same idOras -> collect the newest one (newest sentDate) and remove the others
  • if they have different idOras -> collect both of them sorted by sentDate ASC
• if two Messages have different Ordre :
  • collect both of them sorted by Ordre

for now I'm using this stream :

orasBatchConfiguration.setSortedZbusOrasList(messageList.stream()
            .collect(Collectors.groupingBy(Message::getIdOras,
                    Collectors.maxBy(Comparator.comparing(Message::getOrdreCalcule))))
            .values()
            .stream()
            .map(Optional::get)
            .sorted(Comparator.comparing(Message::getOrdreCalcule))
            .collect(Collectors.toList()));

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