Sellers Portal Script

Have a good day,
SEMrush

Our company sells dairy products and wants to create a portal on which some resellers can connect and place orders.

The website must not display product prices unless the reseller is connected.

The script must be able to export to a custom csv or txt file that we can download and import into our erp system.

What would be the best cms with plugins or mods to create a system like this?

Thanks in advance