Pull multiple values through a lookup

Question

I am rather new with SP so I apologise if I cant express myself too well.
Problem at hand:

Two lists - Shops and Managers with a many-to-many relationship between them.
I.E. in Shops there can be more than one managers and a manager can manage more than one shop

I want to either:

1. Create a List C where I have a lookup column listing each shop in the first column and in another ALL of the managers that correspond to this shop, written in one line.
2. Insert a column in Shops outlining all of the managers per a particular shop.

Essentially I want to create a workflow that is activated on a specific date, which checks whether there has been any change in the Managers or the Shops list and subsequently update List C.

Any idea on how I can get multiple values for a lookup?
I created the workflow, but I can only have one value per a field in Shops for managers.

Answer 1

You should allow multiple values on lookup column:

EDIT:

This will allow you to enter multiple lookup values in the column:

Answer 2

The above is basically correct. In your shops list, create a lookup field to your Managers list, but instead of ID, use the title field (I'll assume your managers name is in that field).

Get information from 
Managers
In this column
Managers Name

When you add a shop, you can select all the managers for that shop. In workflow, if you return that lookup field, you'll have the option to return it as 'Lookup Values (semicolon delimited)', which will be a list of all the managers.