Private Structure GroupPropertys
   Dim sName as String
   Dim sMember() as String
end Structure

Dim sArrGroups() as GroupPropertys

'...
try
   redim preserve sArrGroups(ubound(sArrGroups)+1)
Catch ex As Exception
   redim preserve sArrGroups(0)
end try
sArrGroups(ubound(sArrGroups)).sName = "Gruppenname"
'...

'...
try
   redim preserve sArrGroups(i).user(ubound(sArrGroups(i).user)+1)
Catch ex As Exception
   redim preserve sArrGroups(i).user(0)
end try
sArrGroups(i).user(ubound(sArrGroups(i).user)) = "Username"
'...