This is something
NFS does very easily.
This will permit Products for 10.10.20.* and Customers for 10.10.21.
Code:
# /etc/exports file
/directory1/Products 10.10.20.(ro,sync,no_subtree_check,other_options)
/directory2/Customers 10.10.21.(rw,sync,subtree_check)
Security-wise, this isn't very secure however since a lan address can be spoofed.