I have tried to deploy multiple lambda functions which are in multiple code commit repository to deploy it using single code pipeline. But I am unable to do it.
I tried https://medium.com/hatchsoftware/setting-up-ci-cd-for-lambda-functions-using-aws-codepipeline-880567769dde
But It is working for single lambda not for multiple lambdas
To handle multiple repositories using a single CodePipeline, you can specify one source action per repository. Please also have a look at this answer.
Looking at the CodePipeline setup in the article you mentioned, it would be possible to process the artifacts from all the source actions in the same CodeBuild project (docs), so there is no need to add additional build actions. Same goes for the deploy stage: Assuming you are using CloudFormation, you can manage all Lambda functions in the same stack, so you only need one deploy action.