Covering multiple web applications in cucumber features

I'm writing cucumber feature files and don't have step definitions yet, but planning to add later.

I need to test public and admin web applications sharing common business data. What will be correct way to develop feature files?

feature centric (one feature file for both applications) or
application centric (separate feature files even feature is same)

I fill that former option is better but how difficult will be implementation?

UPDATE:

For example, Blog style application, with comment moderation functionality:

When comment is approved by moderator (in the admin app), user (in the public application) should see push notification about comment approval. So there is a one functionality which affects two applications.

Solution

On an agile project, you organize features by story; one feature file per story.

So ask yourself, how do you organize your stories? Some people answer by business objective, others by epic. Your feature files should be organized in a similar manner.

Cucumber enables Behavior Driven Development (BDD). How much behavior is shared between the public and admin portions of your application? Their objectives might be very different. Group common behavior together (e.g. they both have to authenticate) but don't force uncommon behavior together.