I think it would be a good idea to have the option of grouping tenants for the purpose of organisation and not deployment:

• A group does not have the functionality other than to group items
• Grouping is optional and you would always be able to interact with tenants in the same way you do now
• Groups have a name, description and maybe an image
• A group can contain tenants and/or other groups
• Tenants do not need to be in a group
• Being in a group does not functionally affect the tenant

The scenario:

1. I run a business that puts up websites for other businesses
2. Some businesses are simple and have a single website that represents the whole business
3. Other businesses have a 'brand'/enterprise which requires a website and multiple smaller businesses that it manages each requiring it's own website and while the smaller sub-businesses are live only the top level 'brand' might also have a UAT/Training/QA all under the same tenant

In this scenario Octopus has a single project that deploys a website that gets transformed for each 'tenant'. This works fine on a smaller scale but with 200 customers where some of them have 20+ websites/'tenants' I can become quite a hassle to manage them.

The closest item I could fine to this one is this where a single tenant would always represent the enterprise. But it adds a lot of confusion and I think a simple, optional grouping concept would be a lot more user friendly and accomplish the same goal or organised tenants.