Unable to infer employee-region relation given employees have accounts and accounts belong to region

Hello all,

I am building a standard org. hierarchy consisting of employees, accounts and regions with the following rules:

1) Each account can be assigned with only 1 employee.

2) Each account belongs to only 1 region.
3) Each account for one employee is within one region.

For some calculation purposes, I need to know, to which region each employee belongs. Given the relations described above,
this should be makeable since we know the account-employee and account-region relationship.

I have tried functions like Lookup and Firstnonblank, but both failed as there is no list-formatted line item

in the target module (Employee) which would match the dimensions of the source module (Accounts).

I depicted the schema below:

Thanks for any hints,

Stepan