Use Case for Multiple Developer Accounts

Our insitition is underway on migrating over to Adobe Sign from DocuSign.  We did not opt-in for a sandbox environment and instead went with creating a developer account for our Admins to begin testing integrations and recently discovered the limited number of users that can be within one developer account environment.  I was hoping someone may have figured out how to address the limit of users that can access a developers account.  I would like to invite my template creator/web form creators within my enterprise to have access to a developer's account that I manage.  Possibly create multiple developer accounts with different email accounts.