Learn useful tips for common scenarios:
To the run jobs from multiple GitHub accounts onto the same AWS account, simply adjust the IAM role trust policy to include a list of GitHub accounts instead of a single one:
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "381491863103"
            },
            "Action": "sts:AssumeRole",
            "Condition": {
                "StringEquals": {
                    "sts:ExternalId": [
                        "first-github-account-name",
                        "second-github-account-name",
                        "yet-another-github-account-name"
                    ]
                }
            }
        }
    ]
}