If you’re dealing with linked record arrays, your better bet is to use Rollup fields. Rollups can pre-filter items in the returned array so you can say “only list items where Type = Office”. For the aggregation formula you’d likely want either ARRAYUNIQUE() or ARRAYJOIN() or ARRAYCOMPACT(), or a combination of any of those.

Just to clarify one other point, formulas cannot create arrays. The functions that @Kamille_Parks listed can be used to process arrays, but Airtable does not currently provide any means to make arrays manually.

If Kamille’s rollup field suggestion doesn’t solve your problem, please share more specific details about your base setup and the formula that you’re using to create the output that you listed.

Thank you both for your input. I struggled with trying to explain this so I created a new base and built an example to share. While doing this, I found where I was stumbling. Long story short, I did not have all the ingredients that I needed.