SimEvent MDES access to external Data

I have a SimEvent MDES model that performs custom scheduling based on an external dataset (matrix data imported from Excel). Data has been imported into the Workspace, and can be viewed in the Model Explorer / Model Workspace.

What I am trying to do is use this in the MDES... for example:

entity.AttributeX = MyData(5,9);

MyData is not local to the MDES so it is not recognized, and so far I've found no way to make it vissible there for use.

How can I get the Workspace data into the MDES for use?