Passing Values from Dropdown list or radio buttons

Hello,

I have a dropdown list (Or radio buttons) as such:
1-10
11-20
21-30
31 and more.

Upon submitting the form, i do not want it to pass the values as you can see them above but I want it to send some different predefined parameters such as:

1-10 –> A
11-20 –> B
21-30 –> C
31 and more. –> D

as those values are going to my CRM and for it to understand them, I need them to be in this format.

Can you please let me know how to achieve this?

Cheers!