I want to do select the mp3 file format at 40 k/s... help me

hi to all
i have selected the participants(users) a speed of 20 k/second, and I want to do select only the mp3 file format at 40 k/s up when the participants(users) when they are downloaded … I mean to imply that the speed set them up 40 k/s but the rest of the sites and extensions remain 20 k/s

what i do on the firewell mangle and queuses >>>>please send me the codes of that work

Thank to all

You can’t match file types in firewall.

ok , is there any think to limit mp3 40 k/s ?

no, you can’t

you’d better use Squid