Customer needs information regarding usage of OLAs for groups in requests.
If the Service Types is implemented in your environment in a way they are associated to the tickets; apart from that, generally speaking, the service types can be attached automatically to the ticket when they are associated to the final user, to the category, to the priority.
A ticket can have more than one service type associated, depending on the above.
The service type events associated to the ticket start however at the time the ticket is created; there is however the possibility to delay and then to resume them and when the event expires, it is evaluated and the appropriate actions are taken on the base of the actions set.
A transfer from a group/assignee to another group/assignee doesn’t have an automatic impact on what said about the starting time, delay and resume;
If the purpose is to have a recalculation of the timings on the base of when the transfer to another group has been done or specific settings considering only the time the ticket has been (or has to be) managed in a specific group, that cannot be done, from service type point of view, in the tool out of the box.