Is it possible to have a centralized storage/volume that can be shared between two pods/instances of an application that exist in different worker nodes in Kubernetes?

So to explain my case:

• I have a Kubernetes cluster with 2 worker nodes. In each one of these I have 1 instance of app X running. This means I have 2 instances of app X running totally at the same time.

• Both instances subscribe on the topic topicX, that has 2 partitions, and are part of a consumer group in Apache Kafka called groupX.

As I understand it the message load will be split among the partitions, but also among the consumers in the consumer group. So far so good, right?

So to my problem:

• In my whole solution I have a hierarchy division with the unique constraint by country and ID. Each combination of country and ID has a pickle model (python Machine Learning Model), which is stored in a directory accessed by the application. For each combination of a country and ID I receive one message per minute.

• At the moment I have 2 countries, so to be able to scale properly I wanted to split the load between two instances of app X, each one handling its own country.

• The problem is that with Kafka the messages can be balanced between the different instances, and to access the pickle-files in each instance without know what country the message belongs to, I have to store the pickle-files in both instances.

Is there a way to solve this? I would rather keep the setup as simple as possible so it is easy to scale and add a third, fourth and fifth country later.

Keep in mind that this is an overly simplified way of explaining the problem. The number of instances is much higher in reality etc.