To leverage supply contracts and make MRO supplies available to all subsidiaries efficiently and cost-effectively:

Require suppliers to provide secure ordering portals tailored to specific contracts: While secure, this approach places the burden on suppliers and may lead to inconsistencies in user experience.

Conduct train-the-trainer sessions for supply management staff at the subsidiaries: Effective for training, but not the most efficient way to provide ongoing product details.

Create internal online catalogs with ordering instructions and links to suppliers' sites: This approach centralizes information, making it easily accessible for all subsidiaries. It ensures consistency in ordering procedures and allows for efficient updates.

Email a list of suppliers' websites to contacts at each subsidiary: Simple but lacks centralization and can lead to outdated or inconsistent information.

Therefore, the most efficient and cost-effective way is to create internal online catalogs with ordering instructions and links to suppliers' sites.

References:

Supply chain management best practices on internal cataloging.

Institute for Supply Management (ISM) guidelines on centralized procurement systems.