Value object with set of aggregate roots?

We are working on an administrative system with quite a large amount of aggregate roots. We have a hexagonal architecture, where a single hexagon handles a specific type of calculation using a separate product (and therefore a separate bounded context). Certain calculations performed within this hexagon require a list of roots. The reason for this is twofold:
 This hexagon requires a “picture” of the customer for which the calculation is performed. This picture represents the situation of that customer at a certain moment in time. This includes both personal information about the customer, but also additional information, which in contained within separate roots in the domain model. Another functional responsibility of this hexagon is to create a fictional situation for the provided roots. This can for instance be a future situation, where certain events are being applied to multiple roots ·     

 The question is how to model this picture class containing a set of aggregate roots. Should this be an entity or a value object? A value objects seems the best choice, but this would imply that the picture would be immutable. Given that the picture contains various Aggregates which are themselves mutable, this would not hold. Due to the potential changes in one or more aggregate, one could argue it cannot be a value object, as it is mutable. Modelling this object as an Entity would be the other option. It that case, the question is what the identity of this entity should be. Also, this would imply that we have an aggregate which is built-up out of other aggregates, which also seems like a strange design.