I want to use Google PubSub and Redis PubSub provided by Google Cloud in Javascript GraphQL(apollo-server).

I tried to create 2 subscription fields, but I couldn't get the result I wanted.

this, it said that subscriptions do not provide more than two root fields.

How can I subscribe to 2 pubSub objects?

The code I used is like below.

Subscription: {
    operation: {
      subscribe: withFilter(
        (_, { channelId }, { pubSub }) => pubSub.asyncIterator(getTopic(channelId)),
        (payload, variables) => {
        
            // Some Code...
           
        }
      ),
    },
  },