Is there a way to resolve a reference in a custom validation?

{
  name: 'tags',
  title: 'Tags',
  type: 'array',
  of: [
    {
      type: 'reference',
      to: [{ type: 'artist' }, { type: 'category' }],
    },
  ],
  validation: (Rule) =>
    Rule.required().custom((data) => {
      /*
        That is what i get from the data item. 
        But I need to know the type of the reference (artist or category)
        
        data [{…}]
          0:
          _key: "b29ee1dbb22a"
          _ref: "96e38ca0-b075-4777-b8f4-d2d6ca123df0"
          _type: "reference"
      */

    }),
},

import { uniq } from 'lodash'

...

      validation: Rule => Rule.custom(data => {
        const types = data.map(item => item._type)
        const uniqTypes = uniq(types)
        return uniqTypes.length > 1
          ? true
          : 'Must have at least one of each'
      }),

[{ type: 'artist' }, { type: 'category' }]

import { uniq } from 'lodash'
import client from 'part:@sanity/base/client'

...

      validation: Rule => Rule.custom(data => {
        const referencedIds = data.map(item => item._ref)
        return client.fetch(`*[_id in $ids]._type`, {
          ids: referencedIds
        })
        .then(res => {
          const uniqTypes = uniq(res)
          return uniqTypes.length > 1
            ? true
            : 'Must have at least one of each'  
        })
      }),