Component.vue

<template>
  <form>
    <v-layout row wrap>
      <v-flex xs12 md6 lg6 pl-1 pr-1>
        <form-group name="roles">
          <template slot-scope="{ attrs }">
            <v-select
              multiple
              chips
              :height="33"
              v-bind="attrs"
              :items="roles"
              item-disabled="isDisabled" <!-- la clave para deshabilitar ciertos elementos -->
              v-model="form.roles"
              label="Roles"
              item-text="name"
              item-value="name"
              @input="$v.form.roles.$touch()"
              @blur="$v.form.roles.$touch()"
            >
              <template slot="item" slot-scope="props">
                <v-checkbox
                  :label="props.item.name"
                ></v-checkbox>
              </template>
              <template slot="selection" slot-scope="props">
                <v-chip
                  small
                  :selected="props.selected"
                  class="chip--select-multi"
                  :key="props.item.name"
                >
                  {{ props.item.name }}
                </v-chip>
              </template>
            </v-select>
          </template>
        </form-group>
      </v-flex>
    </v-layout>
  </form>
</template>

<script>
import { required } from "vuelidate/lib/validators";
import includes from "lodash/includes";
export default {
  name: "Form",
  data() {
    return {
      roles: [
        { name: "ROOT" },
        { name: "ADMIN" },
        { name: "CUSTOMER" },
        { name: "GUEST" }
      ],
      form: {
        roles: []
      }
    };
  },
  watch: {
    "form.roles": function(newVal) {
      this.roles.forEach(role => {
        role.isDisabled = false;
        if (includes(newVal, "ROOT")) {
          role.isDisabled = role.name === "GUEST";
        }
        if (includes(newVal, "GUEST")) {
          role.isDisabled =
            role.name === "CUSTOMER" || role.name === "ADMIN";
        }
      });
    }
  },
  validations: {
    form: {
      roles: { required }
    }
  }
};
</script>