How to add or remove user groups from a user on an event?

Question

1C-Bitrix

One user can have several partners. Each counterparty has several user groups. For these user groups, discounts are set that imitate price types (a crutch, but it happened with 1C).

It is required that when a user selects a counterparty, his user groups change.

I found this method https://dev.1c-bitrix.ru/api_help/main/reference/c...
But user groups will be applied only at the next authorization. Is there any way to bypass this limitation and change user groups of an authorized user?

Answer 1

Don't trust Bitrix. SetUserGroup Gets up at once.