Vue でクロスレベルコンポーネント通信を実装するにはどうすればよいですか?

<template>
  <div>
    <ChildComponent :message="message"></ChildComponent>
  </div>
</template>

<script>
import ChildComponent from './ChildComponent';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      message: 'Hello Vue!'
    };
  }
};
</script>

<template>
  <div>
    <p>{{ message }}</p>
  </div>
</template>

<script>
export default {
  props: {
    message: String
  }
};
</script>

<template>
  <div>
    <ChildComponent @custom-event="handleCustomEvent"></ChildComponent>
  </div>
</template>

<script>
import ChildComponent from './ChildComponent';

export default {
  components: {
    ChildComponent
  },
  methods: {
    handleCustomEvent(data) {
      console.log(data);
    }
  }
};
</script>

<template>
  <div>
    <button @click="handleClick">Click Me</button>
  </div>
</template>

<script>
export default {
  methods: {
    handleClick() {
      this.$emit('custom-event', 'Hello Vue!');
    }
  }
};
</script>

import Vue from 'vue';
import Vuex from 'vuex';

Vue.use(Vuex);

export default new Vuex.Store({
  state: {
    message: 'Hello Vue!'
  },
  mutations: {
    updateMessage(state, payload) {
      state.message = payload;
    }
  }
});

<template>
  <div>
    <p>{{ message }}</p>
    <button @click="changeMessage">Change Message</button>
  </div>
</template>

<script>
import { mapState, mapMutations } from 'vuex';

export default {
  computed: {
    ...mapState(['message'])
  },
  methods: {
    ...mapMutations(['updateMessage']),
    changeMessage() {
      this.updateMessage('Hello Vuex!');
    }
  }
};
</script>

<template>
  <div>
    <p>{{ message }}</p>
  </div>
</template>

<script>
import { mapState } from 'vuex';

export default {
  computed: {
    ...mapState(['message'])
  }
};
</script>