I just created a group and checked it in Calcsys. It seems to be oredered like this:
-The first byte was $FC. I have no clue why.
-Next two bytes are the size of the group (little endian)
-Next comes the VAT entry (since it is archived)
**See below for a breakdown of archived syntax**
-After this is the size bytes of the data. This is two bytes in little endian
-After that it is like reading archived variables
Archived syntax: (the 00 means the first byte, 01 is the second byte...)
00-type
01-reserved for future OS changes
02-archived status. This will be 0 since groups can only have vars in RAM selected
03-Address where the var was before grouping. two bytes, little endian
05-forgot, actually, but this seems to be 0
06-size of the var name followed by the name
n-After this is two size bytes, followed by data
Does this help?