Use the Accounts Management option to add your account managers to each of your child companies
Go to Admin > Agency > Accounts Management
To do this, please select this option from the Admin section of your main company/agency. This will prevent you from having to create the same user in different child companies.
Once you are there, you will see each child company listed on the left side of the panel, click on each company to add or remove any account managers.
Once your account managers are set up, click Save.