e.g. database = 'test' measurement = 'm1'
I want to have 1 year retention policy for points in m1 with tag='A', and 2 years retention policy for points in m1 with tag='B'
No, retention policies apply to all records written to them. To accomplish what you want you would need to write points tagged with A to one DB/RP, and those tagged with B to a different one.