Looking for a method of how to best group an issue status

Hi all
I’m new to this game but I’m trying to get MDX working (calculated member) in order to group ticket statuses.

i.e. if status in open, in progress, development then group A, if status in with customer, sales then group B, if status in closed or resolved then group C.

or to put it a different way:
Group A

  • Open
  • In Progress
  • Development

Group B

  • Status Customer
  • Status Sales

Group C

  • Closed
  • Resolved

Or should this be added as a hierarchy in the advanced settings?
Thank you for any suggestions