Merging data from Powershell exports

Hi,

I have a little tricky problem.

I need script with export to csv, where I need information from Get-Mailbox (OrganizationalUnit etc.), Get-MailboxStatistics (TotalItemSize etc.) and Active Directory (Department etc.). If I use pipelines for example Get-Mailbox | Select-Object OrganizationalUnit | Get-MailboxStatistics | Select-Object TotalItemSize, i get only TotalItemSize and I can't reach OrganizationalUnit.

Can someone help me? Some clue or something like that?

Thank you very much