dynamically change which anchor (*composer-install or *composer-update) is used based on $PHP_VERSION in gitlab CI

Here, I have added a snippet of .gitlab-ci.yml, which is performing unit tests for different PHP versions.

So, for the unit test, it is installing the composer dependencies based on different PHP versions.

Now, I want to install composer (*composer-install) when PHP_VERSION = 7.4 otherwise composer update (*composer-update)

I am expecting a solution on how to add anchors conditionally. If not, do we have any alternative method except the one mentioned?

Existing configuration:

.install-composer-script: &install-composer-script
  - composer install
  - composer bin all install

.update-composer-script: &update-composer-script
  - composer update

.composer-install: &composer-install
  before_script:
    - echo 'APP_ENV=gitlab-ci' >> .env
    - ssh-keygen -t rsa -f ./data/id_rsa -q -P ""
    - *install-composer-script
    - composer build-phar
  <<: *unit-tests

.composer-update: &composer-update
  before_script:
    - echo 'APP_ENV=gitlab-ci' >> .env
    - ssh-keygen -t rsa -f ./data/id_rsa -q -P ""
    - *update-composer-script
    - *install-composer-script
    - composer build-phar
  <<: *unit-tests

unit-tests-php74-84:
  image: docker-php-image:php-${PHP_VERSION}
  allow_failure: false
  needs:
    - composer
  before_script:
    - echo 'APP_ENV=gitlab-ci' >> .env
    - ssh-keygen -t rsa -f ./data/id_rsa -q -P ""
    - |
        if [ "$PHP_VERSION" != "7.4" ]; then
          composer update $COMPOSER_FLAGS
        fi;
    - *install-composer-script
    - composer build-phar
  <<: *unit-tests
  parallel:
    matrix:
      - PHP_VERSION: "7.4"
      - PHP_VERSION: "8.0"
      - PHP_VERSION: "8.1"
      - PHP_VERSION: "8.2"
      - PHP_VERSION: "8.3"
      - PHP_VERSION: "8.4"

**Is Working:
before_script:
    - echo 'APP_ENV=gitlab-ci' >> .env
    - ssh-keygen -t rsa -f ./data/id_rsa -q -P ""
    - |
        if [ "$PHP_VERSION" != "7.4" ]; then
          composer update $COMPOSER_FLAGS
        fi;
    - *install-composer-script
    - composer build-phar

**But, I want something like:

unit-tests-php74-84:
  image: docker-php-image:php-${PHP_VERSION}
  allow_failure: false
  needs:
    - composer
  before_script:
    - if $PHP_VERSION" != "7.4" then *composer-install
    - else *composer-update
  <<: *unit-tests
  parallel:
    matrix:
      - PHP_VERSION: "7.4"
      - PHP_VERSION: "8.0"
      - PHP_VERSION: "8.1"
      - PHP_VERSION: "8.2"
      - PHP_VERSION: "8.3"
      - PHP_VERSION: "8.4"