We have done multi company consolidated reports with Access and Pass Through Queries (Same old song). First create a new ODBC driver for each additional company (use sotamas) for the first company (e.g. xxxsotamas, yyysotamas).
Create a PTQ for each table (OpenInvoice, AR_Customer, AR_salesperson??). then create a UNION query to link all the tables together into one table. The create your Crystal report for the customer statement. If you have KS alerts, you could create an alert to e-mail.
While it sounds complicated, it is really quite easy and straightforward.