I believe the purpose of work tables is to workaround to the slow ODBC connection between Sage 100 tables and Crystal. A way to replicate this approach in Sage 100 Premium is to use a stored procedure with parameters.
The store procedure is a SELECT statement and selects from the same tables Sage 100 would when generating the work table.
You can select a stored procedure just as you would any other database table in CR Database Expert.. If you don't see them, Go to File > Options and click the Database tab. Then check the box for Stored Procedures. Now it should show up in your list.
If your stored procedure has an input parameter(s), Crystal Reports will automatically create a corresponding parameter for you in the report and give it the same name as what is in the stored procedure.
For your application, you'd need to determine the best way to pass the selection parameters to the above Crystal Report.