Conditional Deployments at Lambda function Level

### Before opening, please confirm:

- [X] I have checked to see if my question is addressed in the [FAQ](https://github.com/aws-amplify/amplify-hosting/blob/master/FAQ.md).
- [X] I have [searched for duplicate or closed issues](https://github.com/aws-amplify/amplify-hosting/issues?q=is%3Aissue+).
- [X] I have read the guide for [submitting questions](https://github.com/aws-amplify/amplify-hosting/blob/master/CONTRIBUTING.md).
- [X] I have removed any sensitive information from my code snippets and submission.

### App Id

d291nw54kg410u

### AWS Region

eu-west-2

### Amplify Hosting feature

Backend builds, Build settings

### Question

Hi
Is there a way to Have conditional Builds on lambda functions . AMPLIFY_DIFF_BACKEND works only if no changes are made to any lambda but even a slight change to 1 lambda requires a full build of the Backend. This in our case runs over a half hour .
Is there a setting to only deploy the lambda functions that have changed?

Many thanks

Start with FAQ.md and the Backend builds and Build settings material referenced by the issue. Determine whether deployment can target only changed Lambda functions, and document the relevant setting or the scope of the required feature; completion should make the supported behavior or limitation clear.

Written by the indexing model from the issue text.