Inviting individual users from another org when "Check for Project on Authentication" is enabled?

Let's say I have two organizations,

with and

and they both have their own project (

projectA

projectA

projectB

projectB

) and an application (

appA,

appA,

appB

appB

) . In

projectB

projectB

I use

Check for Project on Authentication

Check for Project on Authentication

setting. Now only users of org

can access project

(as intended).

How can I then allow some select individuals of organization

to log in to

appB

appB

? I've tried creating a role in

projectB

projectB

and then authorizing users of

, but I keep getting

Login not possible. The organization of the user must be granted to the project

Login not possible. The organization of the user must be granted to the project

message.