Lookup data from two line items with different format and "applies to" lists.

Hi, 

My current build has been full of surprises. Right now I need to lookup start dates for new employees, but, the module I am building and the model from where I need to take the data, both use different lists. As you can imagine the lookup does not work and I cannot just pull data directly over without a formula. Do any of you have any tips on how I can work around this? 

To explain more in detail. 

I have a module, call it X, with a line item called "employee start date". This module has a flat list called "FL-Employees" (containing all the employee's names). The line item in module X shall draw its data from the line item "employee start date" (date formatted line item) in module Y. But, each date should be identified to an employee, thus, I need to do a formula similar to: Employee start date (in module X) = Employee start date (module Y) [lookup: employee name (also module Y). However, the line item "employee name" in module Y is formatted as a list (the same as module X, FL-employee) and lookup does not work. 

Kind Regards, 

Gabriel Ekman