Hi Renne,
I hope you are doing Planning, not Consolidation:).
You have a number of options depending on multiple criteria:
1. How integrated are those 2 company code? If they are very integrated, i.e. a lot of reports and calculation should be done on union of the two, then you can try keeping them in same Model and create 2 hierarchies on Time Dimension.
2. If most of the planning can be done on each of them separately, then you can try 2 Models with different Time Dimensions. You can join them either in reports or create a Model on top of them.
3. If other Dimension are different between them then 2 Environments could be an option as well.
Regards,
Gersh