I am looking for some suggestions on aggregating data from multiple services. Currently, I have multiple Spring based services that each have some type of stock data (pricing, sector/industry, earnings and revenues). In many cases I need to aggregate data based on a query request that could span multiple services (e.g. price > X and eps > Y). There could be a number of clients, so I don't want to aggregate at in the client layer which is something I have done in the past with some ugly looking code. If you have any ideas or have done something similiar and ran into some gotchas, I would appreciate any advice.