how to define different priority of services

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HI guys, I have about 8 services in one node, and one of the service is really computing consuming and it needs run as quick as possible. But in Ros , i just use nh.advertiseService() to provide the servcer and use call to call the service.

So I am wondering about if I can define different priority of different services (for example like pthread_create()), so I can make this service response as fast as possible.