With LimaCharlie's granular role-based access control you can be granted access in one of two ways:
On a per-organization basis
To a set of organizations using Organization Groups
You'll want to ask the person who granted access if they added you to the individual organizations, or if they'd set up an organization group. Either method works, but they'll have to ensure that either you're added to each organization individually, or that they set up a group.