When I connect Particle to Split node,how can I get the groups for each split particles streams from origianl particle?

You didn't mention if you wanted groups in POPs or after in SOPs.

In POPs, you just append a Group SOP after the Source POP and the Split POP. Group POPs should use the Generator option to create group by particle generator which you have to reference (Source POP, Split POP, Location POP, Spring POP).

If you MMB (Middle Mouse Button) on any POP node, you will see that with two generators in play (Source POP, Split POP), you actually have two different particle primitives. Outside in SOPs, after the POP SOP, you can work on each particle primitive either by group or by primitive number index.

See the attached example file on how to properly set up groups per generator in POPs then how to trivially work on each Particle Primitive in turn.

Thank U~~~~