[rules-users] advice is needed: rule based processing of interconnected facts

Hi, I need some pointer as to where to start with the problem below. The system should be able to validate the balancing data based on around 400 different rules. To simplify the task, the data facts are essentially the debit/credit transactions on different accounts. The rules describe the correlation between different facts: - eg, all debit transactions minus all credit transaction must be equal 0 - if one account got credited, there should be another account (within the same dataset) which was debited - if there are accounts starting with some letter combination, there also should be - etc In other words, each rule describes - the subset of facts to be analyzed - the rules to be checked against this subset It seems basically like each fact is a set of Account Number, Transaction Type, Transaction Amount information, Secondary Account Number (which sometimes needs to be validated against some other account number within the same data set). But I couldn't find a way to relate between multiple data facts. On one hand rule engine seems to be a good solution in here, but I'm not sure how to deal with 'dynamic selection' of the subset of facts. Can this kind of task be reformulated somehow? Any pointers into the DROOLS documentation or hints on a general approach would be greatly appreciated! Thanks. Vlad