Hi Siladitya,
The past discussion I mentioned previously just opposite what you look for start and stop SLA on Group Transfer. That discussion was status of change order could stop SLA event/clock when transfer to the group. In your scenario is have SLA start for "our" group.
I wonder why incident area has SLA but the ca sdm does not have SLA clock start. If the SLA clock is not applied for ca sdm, they could use the suggestion in Stop and Resume SLA on Group Transfer(have status to stop SLA clock for ca sdm when ticket assigned to them). When the ticket transfers to "our" group, have status of the start/resume SLA.
Derek