[Q] Band selection topic

Hello
I want to use only the 900mhz band in wcdma and all band gsm and lte
Or delete the 2100mhz band because my phone no transfert data on this frequence and is the more use in my country :/
But in the selection band menu i can only select 1 band for all and i don't want desactivate lte and gsm an idea?
Sorry for my translation