How to choose a named stage in a Docker file to use by App Platform

I have a mono repo that has a multi-stage docker file and from that I’m trying to deploy two components (web service and static site).

Here is my docker file

FROM mcr.microsoft.com/dotnet/sdk:5.0 AS build
WORKDIR /app

COPY . .
RUN dotnet tool restore

RUN dotnet restore

RUN dotnet publish src/Server -c release -o /deploy/server

RUN dotnet fable src/Client

FROM node:12 AS client
WORKDIR /app
COPY --from=build /app ./
RUN npm install
RUN npm run build

FROM mcr.microsoft.com/dotnet/runtime:5.0 AS server
WORKDIR /deploy/server
COPY --from=build /deploy/server ./
EXPOSE 80
ENTRYPOINT ["dotnet", "Server.dll"]

My webservice component works fine as the **server **stage is the last stage but the static site I’m not sure how to tell App Platform to stop at client

From what I understand you can tell docker to stop at a specific stage.

What is the best way to achieve this using App Platform?