Unfortunately, the entity generator's 'Generate' event action cannot use the values from the generation triggering entity. I have however been able to use Simulink Functions to create getter and setter functions to write and read values from the event actions:
I have called setVal(1, 2, 3) from the terminator's entry action and then called [v1, v2, v3] = getVal() from the entity generators 'generate' event action to read the values. However, this has some pit falls. If another entity arrives at the terminator with a higher priority than the generate event, then the values in the simulink function get overwritten. I haven't been able to figure out a better way. Hope this helps!