Grouping column containing Number values into specific subgroups

[Sonny Thind]

i have a dynamic column with ageing number of Days listed, I am trying to Group these according to specific criteria
i.e
Less than 30 days
31 to 45 Days
46 to 70 Days
71 to 99 Days
>100 Days
this criteria will remain Fixed throughout
A pivot doesn't provide specific criteria as the group criteria are not fixed .. is there another method i could use to do this?