Dont know clearly what you are asking . if it is use it.

If you want to know id of group created form UI. Go to  settings -> Sequences & Identifiers -> External Identifiers

and search as res_groups . in search results you can see you group.

Complete id will look like __export__.res_groups_40  (in your case number will be changed.)

then you can use this id as

<field name="name" groups="__export__.res_groups_40"/>