This support article will highlight how to limit a registration type to only be used by selected organisations.
1. By invitation option is found under the details section of a registration type. You can either edit an existing Registration type or input the details when creating a new Reg type
2. Select By Invitation (Nominated Organisations only)
3. You can then select the relevant organisations that sit underneath you to have access to this registration type. 
4. Please note that if you have selected the By Invitation option you must select at least one organisation.
ℹ️ Once you have created or edited your registration type with this option please make sure it is approved (if applicable) at the level above.
ℹ️ The organisations selected will only be able to see this Registration Type when building products/types.