You won't be able to share with an OU that the laptop is unaware of. You may get this to work by trying this;
Use the netbios portion of the domain name for your laptop's workgroup name, if your domain name is MyDomain.lan, then make your laptop's workgroup name MYDOMAIN.
Then add one of the OU members username and password to the local "users" group on your laptop, grant the local users group appropriate permissions to the share on the laptop and test to see if that domain user can access the share.