First see Adding Github Actions to a repo
If you have a repo or a job that is inappropriate to run on a shared resource, you may contact it@tufts.edu and request ESCP to create a custom private runner.
For ESCP:
To create a restricted access Runner Group:
Go to the Organization. Settings > Actions > Runner groups.
Create a new runner group.
Edit the group properties, and select which permissions to apply. (Which repos are allowed to use this runner group)
Then under Runners, edit the Runner Group of the specific runner.