How to add parent layout into XAML only for IOS

Hello guys, I'm trying to add into a XAML file a parent layout.
I have a layout that I want to remain like this in Android
< StackLayout >
//code
< /StackLayout >

while in IOS I would like to add another layout as parent:
< ScrollView >
< StackLayout >
< /StackLayout >
< /ScrollView >

I know that there is the OnPlatform property for the content view but I would like to not duplicate all the code of the layout 2 times since is a lot of code.
Is this possible? Or duplicate all the code with the OnPlatform is the only one solution?
Thanks