Creating subsets of a Region

[ennielion]

Hi I need to make a value looking like the screenshot, but I can't get it done.
![Screen Shot 2020-04-02 at 15.15.34|290x93] (upload://qlUUoKAXSRZ2TbHtGH2Ps8ypzKS.png)

nametree(mpg_sampleRegionHiearchy)
All
├──Region 1
└──Region 2

Thanks so much in advance!

[nirgrahamuk]

mpg_s <- list(
  `Reg 1` = "",
  `Reg 2` = ""
)