limit attachment size exchange 2013

hi all , 

i have exchange 2013 installed and i have one distributed group i need them to send each other and receive message from outlook and owa with attachment more that 50 MB  , i have changed the Organization Transport Setting and this cause all to send more that 50 MB not only the group .also i have run the below command to change the Maxsend and MaxReceive for the distribution group and still they are not able to send more than 30 MB . any idea how to allow distributed group on exchange 2013 to send and received message with 50 MB attachment from Outlook and OWA  

Thanks All