I have this below shown price book which is grouped by its category. I want to sort it manually using a formula and not the specified order because it takes too long there are hundreds and hundreds of such categories grouped.

As you scroll to the bottom left there are many other categories like SS-272 SS-286 we also would like to bring those categories up.

I saw a post where this person creates a formula field and assigns a value '1' '2' '3' to records and then groups sorts and hides the group. But I was not able to achieve it.

Thanks