You are trying to restrict access to records.
1. Standard roles - Select the right role in NetSuite by user. This means you use standard roles that have pre defined restrictions. These are quite robust. (Warehouse manager, buyer etc.)
2. Custom roles - You could also get the same by custom roles - only issue is - this is tedious and permissions/ restrictions can get pretty ugly and intertwined. Could require a fair bit of trial and error. And if you’ve got a lot of different roles, then that is a time drain.
1. Groups - Maybe you can create groups of users, where a group has access/ restriction to records. May need to play with this to ensure it works
Hope this helps