Get-ADGroup not showing all properties that are displayed when using ADSIEdit

We are using some additional AD Object attributes to track object ownership. For example when I use ADSIEdit to view the properties for an AD group I see the attribute names:

MIISGroupPrimaryOwnwerName
MIISGroupSecondaryOwnerName

However, when I issue the PowerShell command:

get-adgroup "groupA" -prop *

I do not see these attributes listed. In fact there are many attributes that I see in ADSIEdit that I don't see when I run the PowerShell command listed above.

Using ADSIEdit i added a value to the attribute 'MIISGroupSecondaryOwnerName'. Now when I run the PowerShell command the attribute is displayed (with the value I added).

So seems to be that get-adgroup "groupA" -prop * only shows attributes populated with values.

Is that a correct statement? Is there a way using PowerShell to show all the attributes (populated or not) that I see when using ADSIEdit?

Thanks in advance for any help you can provide.