Suggest to limit external invitation to only admins.

[Rosalle]

Currently, Asana team members are able to invite either external guests or they can invite new members with the same email domain but incorrect first/last name. This recreates multiple available members in the workspace.

[Jan-Rienk]

Hi @Rosalle,

This currently is possible (or will soon be, when it rolls out to your instance) with Role Based Access Control

For this you will currently need either Enterprise+ or teh permissions management add-on.

Also see:

Introducing role-based access control with custom roles!

Hi Asana Community! We’re excited to introduce Role-Based Access Control with Custom Roles, a powerful new way to manage access and permissions across your organization! This update brings: Centralized control: Manage organization-level permissions from the admin console Enhanced security and compliance: Meet security and compliance requirements with granular control over role permissions Standardized workflows: Create standardized ways of working across your organization by defining appropr…

[Rosalle]

Thanks! Seems applicable for our use case!