Select identity upon recipient

Dear all,

I was looking for a way to avoid sending e-mails with the incorrect identity 
in Kmail and thought about linking identity to recipients. Turns out someone 
thought about it 7 years ago:
http://kdepim-users.kde.narkive.com/vgvg5uki/select-identity-upon-recipient-in-kmail

The response at the time was to wait for the new kdepim, which is now the 
current one I believe. Is this still problematic to implement? It would be a 
damn nice feature for people having many e-mail accounts!

Cheers,
Pierre.