Since Google has its own customer id linked to each account, it has
nothing to do with your own customer id's in your own system.
Unless you have a local table where you link each of your own customer
id's to the google id's or loginEmails, the only way would be to read
the primary adress data from each account and compare it with your
local data - if there is a match you got the accounts. But that method
would probably eat up some quota if you have many accounts to manage.
Regards,
Christian