Here is a funny workaround, as:
person "person" <<p>>
rectangle "comp green" as cg <<zoneGreen>>
rectangle "comp red+green" as crg <<zoneRed>>
rectangle "comp red" as cr <<zoneRed>>
person -> cg
And it shows some defects on the styles of nested elements (cf. card vs group )
No other group or nested elements are possible without green border !!!
If that can help, but it is only a demonstrative workaround...