Nested lists: get selected item of inner list? - sapui5

Question

As part of my SAPUI5 application i have a list which can be used to navigate to detail pages for the selected item. Now for every list item there is also a choice for a "mode" which can be selected from a list aswell (=> nested list).
This is how the view looks like:
<List id="competitionList" items="{
path: 'competitions>/results'
}">
<items>
<CustomListItem
type="Navigation"
press="onPress">
<VBox>
<Text text="{
path: 'competitions>time',
formatter: '.getDescription'
}"/>
<SelectList id="mode-select">
<items>
<core:Item key="full" text="Full"/>
<core:Item key="one" text="Short"/>
</items>
</SelectList>
</VBox>
</CustomListItem>
</items>
</List>
As you can see there is a SelectList inside the standard List. That SelectList will be filled according to some values inside the bound competition.
Now my question is: How can i determine which item got selected in the SelectList inside the onPress function for the pressed item of the parent List?
My onPress function currently looks like this:
onPress: function(oEvent) {
var oItem = oEvent.getSource();
var oRouter = sap.ui.core.UIComponent.getRouterFor(this);
oRouter.navTo("startlist", {
showId: showId,
competitionId: oItem.getBindingContext("competitions").getProperty("number")
});
}