Grant space access permissions to the user group of another Confluence site

[gracefoo]

Will it be be possible to grant space access permission to the user group of another Confluence site?

I would like the users of Confluence site A user group confluence-internal-users to access one of the spaces from another Confluence site B

May I know how can I achieve this without having to manually invite all the users from site A to site B? Because there are over 500+ users and this will take up alot of our effort in future management of onboarding and offboarding users.

We do not want to use invitation links to invite the users as well as this will take up significant costs. 

Are there any other solutions?

Thanks!

[Brant Schroeder · Accepted solution]

@gracefoo I would suggest using Atlassian Access.  This will provide the features that you are looking for,  https://www.atlassian.com/software/access 

[Brant Schroeder]

@gracefoo can you accept this answer to help others?