Yes! This feature was released with Toast POS v 1.9.3.
Now, from the either the setup page for the Modifier Option or the Advanced Properties Page, a course can be assigned to a Modifier Option.
On the Modifier Option setup page, this is found under the heading "Preparation". By default a Modifier Option will inherit its course from the item it modifies. To edit this, select "No, specify course here" and choose a course from the ones that are already configured.
This can also be done on the Advanced Properties bulk editor page. Simply expand the Menu, Menu Group, Menu Item and Modifier Group to find the Modifier Options. Using the Course column (Shown by default) you can specify a separate course for each Modifier Option.
This feature may not be applicable in all scenarios, but it certainly helpful to Menu Items with items that come out ahead or behind the main item. For instance, in the example above, the Sirloin Steak is the Entree item, but the salad options are designated as Appetizers and the dessert options are designated as desserts.