how combine multiple properties from one array to another

im trying to script for rodc , which will schedule connect through vpn and see which password was changed last time, if password changed, it will replicate them , so ,,

lets say i have,

$adusers = $users | Get-ADUser  -Properties  PasswordLastSet | select ` SamAccountname,PasswordLastSet,PasswordCached

and previously saved csv  file  

$lastfile = Get-ChildItem  $logpath -Recurse | where {$_.LastWriteTime.ToShortDateString() -eq (get-date).ToShortDateString()}
$lastsync = Import-Csv $lastfile
$us = Import-Csv $lastfile | select samaccountname,passwordlastset

so,

for compare these properties i want combine these  two arrays ,  specially : 

i want  $us.passwordlastset  to add $adusers.passwordcached  property and get  one hash table. could please help me, how can i achieve this?   multiple properties object from one array add to another proper object  properties

cause  i want  it in one array  is that , i  want  filter  with  "  | where {$_.passwordlastset -ne $aduserpasswordcached} 

Thanks,,