Not deleting sent messages when deleting conversations

I am noticing when I use the conversations view, which makes it more clear to keep track of back and forth email replies, that it deletes the sent messages along with received messages when deleting the conversation. It would be nice to have control over this because in all other programs I have used, deleting a conversation/thread only deletes the received messages and there is still a record of the sent messages in my sent folder. Seems odd to me that anyone would want to delete a sent message along with others in the conversation and loose the record of a reply.