Xbox game pass Ultimate problem account

If you opt to get ultimate it will also convert your gold account to an ultimate account going forward.

Xbox Game Pass Ultimate FAQ

The only problem with that is, it will whine down to (I think) 4 months of Xbox game pass ultimate because somehow I merged game pass ultimate WITH Xbox live. I’m trying to UNMERGE it with only Xbox live and NO game pass ultimate. Any tips how to do that?

Your first month is $1. After that, the subscription will charge at full price.

Note: A purchase of Xbox Game Pass Ultimate automatically upgrades your existing Xbox Live Gold or Xbox Game Pass memberships to Xbox Game Pass Ultimate. When you join Xbox Game Pass Ultimate, we will apply any prepaid time you have on Xbox
Live Gold and/or Xbox Game Pass toward Xbox Game Pass Ultimate, up to a maximum of 36 months.

For example, if you have 3 months of Xbox Live Gold and 3 months of Xbox Game Pass already on your account when you purchase your first month of Xbox Game Pass Ultimate, you will have a total of 7 months of Ultimate on your account before you need to renew
your membership.

When you join Xbox Game Pass Ultimate, we will apply any prepaid time you have on Xbox Live Gold and/or Xbox Game Pass toward Xbox Game Pass Ultimate, up to a maximum of 36 months.

For example, if you have 3 months of Xbox Live Gold and 3 months of Xbox Game Pass already on your account when you purchase your first month of Xbox Game Pass Ultimate, you will have a total of 7 months of Xbox Game Pass Ultimate on your account before you
need to renew your membership.

https://www.microsoft.com/en-us/p/xbox-game-pass-ultimate/cfq7ttc0khs0?activetab=pivot:faqtab

If i understand the problem, you want to buy them both an Xbox Game Pass subscription to play on their respective PC's ? Buy an Xbox Game Pass PC sub for each or a Ultimate Game Pass. Log their account on Xbox beta app on PC and buy them the correct sub.
Or use xbox.com with their account correctly sign in and buy them Xbox Game Pass for PC.