How do I add an AD attribute to my get-csuser filter?

Hello,

I'm trying to extract a list of users that are assigned to a few specific pools, and export that data to a CSV.

The info I need in the CSV are their names, pool they are assigned to, their distinguished name, and also the attribute called "CountryOrRegionDisplayName" which is visible by doing a get-csADuser cmdlet but not in the get-csuser cmdlet.

Here's what I have running, and it works great:

get-csuser -filter {
    registrarpool -eq "pool1.mydomain.com"-or
    registrarpool -eq "pool2.mydomain.com" -or
    registrarpool -eq "pool3.mydomain.com"} |
select samaccountname, firstname, lastname, registrarpool, distinguishedname |
export-csv biglist.csv -NoTypeInformation

Now the only thing I need is to include the country that the user is located in, which is contained in the Active Directory attribute "CountryOrRegionDisplayName" which is totally included in the get-csADuser cmdlet, but not get-csuser.

How could I add "CountryOrRegionDisplayName to the list of things I select?  As in something like the following, which obviously doesn't work:

select samaccountname, firstname, lastname, registrarpool, distinguishedname, countryorregiondisplayname |

I read a little about -ldapfilter but was confused if I could use that with get-csuser, or if I had to do a get-csaduser and try to pull Lync attributes, etc...

Any help pointing me in the right direction would be appreciated!

Thanks,

Brandon