What you are talking about is company consolidations, you need to consolidate 3 companies into 1 parent company.
There are many options:
1. Use software like Accpac Insight or F9 to create a virtual consolidated (parent) company, it's virtual because it does not create a 4th consolidated Accpac company to report from.
2. Use Accpac's GL Consolidations to consolidate the 3 companies into 1 Accpac company, this is a real company within Accpac from which you can do your reporting. GL Consolidations exports the GL transactions from the subsidiary companies and imports them into the consolidated company.
3. Apply your own variations of above options:
a) Write your own program to create a store of consolidated transactions to report from.
b) Write your own consolidation program to produce a 4th consolidated Accpac company to report from.
c) Use a 4th company in Accpac, export the actual transactions or net movement from the subsidiary companies and then import them as a budget in the consolidated company. Your reports will be generated from the budget set, but they contain the actuals.
My personal favoutite is GL Consolidations, mainly because I worked on the original design and development (before Accpac purchased it), but it also provides flexibility when consolidating companies.
Just as a side note, Crystal is very good for general reporting, but so not so hot for financial reporting, the better tool for this is Accpac's Financial Reporter (run in Excel and free with Accpac), or other tools like Accpac Insight or F9 (which you need to purchase separately).
Just my 2c on the topic.