Add Imported Node to Menu

I'm trying to add about 2,000 nodes - using Organic Groups - (in batches of about 50 each). I also want each node to have a menu parent item, so My Menu looks like:

Group
- Sub Group // already created
-- Sub Groups A - F // just a link to the sub-groups of above
-- Sub Groups G - O // as above
-- Sub Groups P - Z // as above
--- Sub Sub Group // this is the groups I am importing/creating now

So, I want Menu Link Title to be for example "Sub Sub Group" and the menu link to be to the new node/group created.

I think I've tried everything (but obviously I haven't).

Any help, much appreciated.