Hi Jonathan,
Inorder to set the focus to the desired button on a SplashPanel,I tried with this.buttonAdv1.Select (); and it works fine here.You can have a switch case as mentioned and can have multiple choice also between the buttons as you wish.
Could you please take a look at the sample attached and let us know if you have any difficulties.
Sample
Thanks for choosing Syncfusion products.
Regards,
Anu.