Compose: Add support external links in docker-compose.yml

Step 1

State containers on host : API is ready

CONTAINER ID        IMAGE                                 COMMAND                CREATED             STATUS              PORTS                         NAMES         
9b463eaae4a6        cedvan/nginx-php-fpm:1.4.6-5.5.9  "/bin/sh -c 'php5-fp   7 minutes ago       Up 7 minutes        80/tcp, 443/tcp              project_api_1  

Step 2

docker-compose.yml on back project :

back:
    image: huttopia/nginx-php-fpm:1.4.6-5.5.9
    ...
    links:
        - project_api_1:api

Step 3

Result of fig up -d back :

Service "back" has a link to service "project_api_1" which does not exist.

Question

Is it possible to add support external links in docker-compose.yml ?