Technically, no. However there is a way...
You need to have both horses on separate accounts, and you need to have Pokémon home on your switch.
Put Glastrier in a box.
Log into your other account, the one that has Glastrier
Put Glastrier into the HOME box at the left
After that, go onto your main account and then transfer Glastrier from HOME to your Boxes. This also applies to Urshifu forms and regular ability starters as well.
Source: Experience and a few videos that I can't find anymore
Hope this helps :)