Simultaneous Entity Creation with Simultaneous Attribute Assignment

I am implementing a polling algorithm using SimEvents. The algorithm periodically consults a table to determine if one or more remote systems needs to be polled. If a poll is required then an SimEvents entity needs to be generated and data from the table added to attributes added to an attribute on each entity being created. Each entity will have unique data, and it is possible that more than one entity is generated at the same instant.

I am able to generate simultaneous entities using the Time-based Entity Generation block or custom function blocks. I have not, however, figured out how to get the unique data for each table entry into each entity. Presenting the table data to a DEMUX block or Resize block to be serialized doesn't work because I have variable size data as input. I have also tried fixing the size and marking entries as "invalid", but they I run into problems with DEMUX and/or Resize not working with the Timed-to-Event and/or Event-to-Timed gateways.

Does anyone have some pointers on to approach this problem?