When you export the model to the MATLAB workspace, by right clickin on the model in SimBiology and selecting 'Export Model to Workspace', you should get a variable m1 (default name) in the MATLAB workspace.
You can explore m1 on the MATLAB command line e.g.:
etc. If you type m1. and hit the <tab> button on your keyboard (don't forget the period after m1!) you can see all the different methods (starting with a lower case letter, e.g. adddose) you can apply to m1 and the different objects within m1 such as Species, Compartments, Events, Parameters etc. However, Doses and Variants will now show up in the tab-complete because they, together with variants, are a hidden property of a model.
repeatdoses = sbioselect(m1, 'Type', 'repeatDose')
scheduledoses = sbioselect(m1,'Type','scheduleDose')
Let me know if that works for you.