A single-select or multi-select field in a Project or a Portfolio has Filter, Sort and Group options:
A reference field in a Project unfortunately does not currently have Filter, Sort or Group options:
But when that same reference field is added to a Portfolio, it has a Group and Sort 
Sort doesn’t seem to do anything, either ascending or descending 
And when I click on Group either ascending or descending, Asana crashes 
I suspect that both of these options should not be available in a Portfolio, although it would be great if they were.. and in projects!
Kindly asking the @Forum-team to escalate as a bug and confirm what the expected behaviour should be.
Thanks!
Hi @Richard_Sather, I’ve submitted this internally for review and escalation. I’ll update you as soon as I hear back on the expected behavior or any findings from the team. Thanks! 
@Richard_Sather - Can confirm all of the above. I too would like for group, filter, and sort functions to support Reference field types in both Portfolios and Projects.
Hi @Richard_Sather, thanks again for reporting this issue! Our product team has confirmed it has been fixed, please let us know if you are seeing the same bug. Hope this helps! Thanks!
Oh awesome! Grouping by reference field appears to be now available for both Portfolios and Projects!
Thanks for the conformation, @Emily_Roman
Kudos to the team 
PS: The order Ascending / Descending doesn’t seem to be respected (A-Z) and also the option is not available within the Group button itself. It’s only available within the dropdown menu of the reference fields’ header.