concatenating web services

hello everybody,

i would like to know, whether it is possible to pipe the output of one web services to the input of the other web service.

imaging you want to know the average temperature of city x on 31st december over the last 20 years.
there are two web services ws1 and ws2.
ws1 provides the temperatures and ws2 calculates the average of list of numbers.

i want to avoid that the client c gets all the temperature data from ws1 which it then sends to sw2 which calculates the average and sends the answer to c.
i would rather like to tell ws1 somehow (how? that is actually my question) to send its output (list of temperatures) to ws2 and not to c. 
ws2 must be able interpret it as its input and must know that it should send its output (average) to c and not to ws1.

i will appreciate any comments and ideas that give me more insight in this matter.

best regards.

sudhir.