Why not make sure to get along time with each of them?
So, sunday morning you take the older one to a lake and sit and talk a little bit. Sunday evening you take the younger one to a nearby park.
Or even just doing an errand together, going to the backyard, doing laundry. You can give them each a chore to do with you to help out (even if it ends up taking more time). DOn’t pick something noisy like vacuuming though.