Eclipse RCP: add optional dependencies

I have open source project Nodeclipse on GitHub I want that during plugin installation, user can select optional features, like Markdown support, JSHint and other plugins that have their own update site.

How to do that in Eclipse RCP plugins?

I guess I need to configure feature.xml in org.nodeclipse.feature

UPDATE:

Do I need to start using Tycho for that?

Selection

Example of Perforce installation

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Not sure if that is even possible.. You can however split your feature into more than one features. So the user can choose what to install.