$ABQ = Get-ADUser -filter * -searchbase "ou=Albuquerque,ou=Users,ou=Corporate,dc=ourcompany,dc=com" |select samaccountname |sort-object samaccountname
$RSW = Get-ADUser -filter * -searchbase "ou=Roswell,ou=Users,ou=Corporate,dc=ourcompany,dc=com" |select samaccountname |sort-object samaccountname

$Results = @(@{Site="Albuquerque";Users=$ABQ})
$Results += @{Site="Roswell";Users=$RSW}

$(foreach($ht in $Results){new-object PSObject -Property $ht}) | Format-Table -AutoSize -Property Site, Users

#Sample Output
Site        Users
----        -----
Albuquerque abqso1
Roswell     {rswde1, rswde2, rswde3, rswde4...}