Multirows and sort for specific column

Hello everybody,

I'm french so, please, don't be afraid by my sentences mistakes ^^'.

I'm trying to do some things with datatables but I don't know if it is possible.

First, I would like to have rows with rowspan like that :

http://sdz-upload.s3.amazonaws.com/prod/upload/demande001.png

Then, I wish to offer to sort only for some column like that :

http://sdz-upload.s3.amazonaws.com/prod/upload/demande01.png

Do you know if it is possible ? And if yes, how ?