I can't tell you precisely how to solve this but, based on my experience with EDEN, I can give a few pointers you can explore to resolve this.
It contains all the import XSL and sample CSV files. Reading through the XSL you can get a sense of what data is required and how they are related and how you should define your CSV files.
2) Furthermore, given that EDEN model is built on an RDBMS you may require importing more than one CSV. From the database, you should be able to make the connections. The tables you may want to investigate are prefixed with "pr" (person) and "hr" (human resources). Within this subset of tables, your tables with names like pr_groups and so on that are integral to formulating the hr_groups you desire.
3) If you intend to import the CSV files through the GUI then you may have to do multiple uploads. The good thing is it would visually present any errors and conflicts in the data.
There are other methods for example placing the CSV files in a folder and running "clean" or "migrate" type scrip to import the data through a preload or post-load CLI mechanism. Fixing errors can be a bit laborious. Once you figure out step 1 and have defined the CSV files and want to move forward, I can investigate deeper into an efficient way to help you with bulk load without using the GUI.
If this doesn't help let us know and we'll see how we can simplify this for you.
cheers
Nuwan