Lets say I receive an xml request that is sent to my web service and this request contains some data in it such as Hotel Room/Rate pairs (Room = Double Queen, Rate = 10%). The database has all of these Room/Rate pairs stored, so when the xml request comes in, I have to validate them to see if the request contains both the room and the rate in the database. If I receive one room/rate pair and it is not in the database, I fail the message and send back an error response, but if I receive 3 room/rate pairs for example, and 2 are found in the database, but one is not, I would process the succussfull ones and send back warnings for the ones that were not found. The other scenario is if I receive 3 room/rate pair and they all are not found in the database, then I want to send back an error message. What is the best way to approach these scenarios?