Assuming that all possible customers are present in the company from which you are running the report, then you could do something like this.
Personally what I like to do when creating reports like this, is to start by adding the data I need to a buffer table (a temporary table is free in the sense of object numbers 50000-99999 and is not required in the license). You would then add the fields to the buffer table, which you need in your report and so working with the data in the report designer is also much easier.
If the customer ledger entry table is where you have most of the fields, then you could make a short cut, by creating a copy of this table and remove the fields you do not need. Add the company name as a field to this table also.
IF Cust.FINDSET THEN
IF CustLedgEntry.FINDSET THEN
UNTIL CustLedgEntry.NEXT = 0;
UNTIL Company.NEXT = 0;
UNTIL Cust.NEXT = 0;