cross-account eventbus design

bus-account-a.yml

Resources:
  Bus:
    Type: AWS::Events::EventBus

  BusPolicy:
    Type: AWS::Events::EventBusPolicy
    Properties:
      EventBusName: !Ref Bus
      StatementId: AllowOrg
      Statement:
        Effect: Allow
        Principal: "*"
        Action: 
          - events:PutRule
          - events:DeleteRule
          - events:DescribeRule
          - events:DisableRule
          - events:EnableRule
          - events:PutTargets
          - events:RemoveTargets
        Resource: !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:rule/${Bus}/*
        Condition:
          StringEquals:
            aws:PrincipalOrgID: o-yourorgid
          StringEqualsIfExists:
            events:creatorAccount: "${aws:PrincipalAccount}"

Outputs:
  Bus:
    Value: !GetAtt Bus.Arn

rule-account-b.yml

Parameters:
  RemoteBusArn:
    Type: String
  LocalBusName:
    Type: String
    Default: default
    
Resources:
  RemoteRule:
    Type: AWS::Events::Rule
    Properties:
      EventBusName: !Ref RemoteBusArn
      EventPattern:
        detail-type: [some-detail-type]
      Targets:
        - Id: localbus
          Arn: !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:event-bus/${LocalBusName}
          RoleArn: !GetAtt CrossAccountEventBridgeRole.Arn

  CrossAccountEventBridgeRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: events.amazonaws.com
            Action: sts:AssumeRole
      Policies:
        - PolicyName: PutEventsOnLocalBus
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action: events:PutEvents
                Resource: !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:event-bus/${LocalBusName}

  LocalRule:
    Type: AWS::Events::Rule
    Properties:
      EventBusName: !Ref LocalBusName
      EventPattern:
        detail-type: [some-detail-type]
      Targets:
        - Id: queue
          Arn: some:sqs:queue:arn....