You could potentially use the block's UserData to share data between the block and another function. See the example on this page. In your GUI, you can use something like:
set_param('path/to/block','UserData',handles.ge);
or
set_param(blockHandle,'UserData',handles.ge);
To set the data.
In the S-function callback methods, you can use:
ge = get_param(block.BlockHandle,'UserData');
To retrieve the data.
