{
    "Type": "AWS::Lambda::Function",
    "Properties": {
        "Code": {
            "S3Bucket": "",
            "S3Key": ""
        },
        "Handler": "index.handler",
        "MemorySize": 1024,
        "Role": {"Fn::GetAtt": ["IamRoleLambda", "Arn"] },
        "Runtime": "nodejs",
        "Timeout": 6
    }
}

{
    "Type": "AWS::Lambda::Function",
    "DependsOn": [
        "IamRoleLambda"
    ],
    "Properties": {
        "Code": {
            "S3Bucket": "",
            "S3Key": ""
        },
        "Handler": "index.handler",
        "MemorySize": 1024,
        "Role": {"Fn::GetAtt": ["IamRoleLambda", "Arn"] },
        "Runtime": "nodejs",
        "Timeout": 6
    }
}

Make Lambda functions dependant on IAM role
Make Lambda functions dependant on IAM role