Selectivity distribution between analog filter and digital filter

Hello, we are designing LTE front end receiver and we are trying to determine the gain of the system which depends on the dynamic range on the ADC. The LPF before the ADC is supposed to decrease the blockers level to some extent and the rest can be removed by the digital filter after the ADC. But we don't know how to distribute this selectivity between the filter. Any help please?

I always used the LPF filters to filter 2H and higher harmonics to more than 70dBc.
It's better to have more depressions on harmonics before ADC. Don't depend on the filter after ADC.