Loop/Iterate in Dockerfile

I'd like to include and enable some custom plug-ins in an official docker base image of an application.

Here is how directory structure looks like;

.
+-- Dockerfile
+-- plugins
|   +-- plugin_1
|   +-- plugin_2
|   +-- plugin_3
|   +-- ...
|   +-- plugin_n

Dockerfile looks like the following if I need to include plug-ins plugin_1, plugin_3, plugin_7 and plugin_8;

FROM myapp_officialimage

COPY plugins/plugin_1/* /usr/lib/myapp/plugins/
RUN myapp-plugins.sh enable plugin_1

COPY plugins/plugin_3/* /usr/lib/myapp/plugins/
RUN myapp-plugins.sh enable plugin_3

COPY plugins/plugin_7/* /usr/lib/myapp/plugins/
RUN myapp-plugins.sh enable plugin_7

COPY plugins/plugin_8/* /usr/lib/myapp/plugins/
RUN myapp-plugins.sh enable plugin_8

CMD ["myapp-start.sh"]

Question is, is it possible to iterate/loop over a list in order to eliminate boilerplate above?

For example, Dockerfile like below would be cleaner and more maintainable;

FROM myapp_officialimage

ENV CUSTOM_PLUGIN_LIST="plugin_1 plugin_3 plugin_7 plugin_8"

for plugin in $CUSTOM_PLUGIN_LIST; \
do \
    COPY plugins/$plugin/* /usr/lib/myapp/plugins/ \
    RUN myapp-plugins.sh enable $plugin \
done

CMD ["myapp-start.sh"]