Defining API Gateway resource in new service based on existing RestApiId

I have one serverless app with existing apiGateway ( generated by serverless framework).
Now I want create others few sls app. All applications should use existing apiGateway.
I want create new repo with api gateway resources configured but I can’t link it to existing api gateway, framework always create new api gateway. Can I define AWS::ApiGateway::RestApi Name for existing api-gateway ?

Current code:

resources:
  Resources:
    MyApiGateway:
      Type: AWS::ApiGateway::RestApi
      Properties:
        Name: "${opt:stage, self:provider.stage}-gateway"    
  Outputs:
    apiGatewayRestApiId:
      Value:
        Ref: MyApiGateway
      Export:
        Name: MyApiGateway-restApiId

    apiGatewayRestApiRootResourceId:
      Value:
        Fn::GetAtt:
          - MyApiGateway
          - RootResourceId
      Export:
        Name: MyApiGateway-rootResourceId

Yes you can. This should help: https://serverless.com/framework/docs/providers/aws/events/apigateway/#share-api-gateway-and-api-resources

@garethmcc thx for answer. In my comment above I have yml config based on documentation you linked but it’s not answer my question. I know how to define shared api with new api gateway.
My question is how to define resources in new serverless app based on api gateway created on old serverless api. I want move this api gateway config to new repo because old will be removed. I tested it in develop branch and when I remove old sls repo api gateway too was removed.