[RL] Can't have a deceased married couple display as such in family tree.

Okay, so you if you have Royalty and Legacy, then you're probably aware that a number of Sims in the game (mostly the pre-made Sims for this pack) have a number of predeceased ancestors that appear in their family tree. And if these ancestors were married, the family tree clearly indicates this. For example, the parents of Tybalt Capp and Juliette Monty were Caliban and Cordelia Capp. They don't exist in the game, but the Capp family tree shows that Tybalt and Juliette's biological parents were married to one another (rendered as a line between them through a pair of wedding rings).

The problem I'm having is that I'm unable to simulate this sort of thing with living married couples in the game upon their deaths.  I'm trying to kill off Cordelia V and her husband Thiago because I'm playing out a storyline involving their children (which I created since they didn't have any) squabbling over inheritance.

Now, killing Cordelia and Thiago isn't the problematic part. That's easy enough to do. The problem is that once they're both dead and gone (netherworld), I can't get them to display as a deceased married couple in the family tree. It only indicates that they were biological parents to their children, but it doesn't indicate  that they were married to one another.

I've tried everything I can think of, but it seems the mechanics of the game don't allow for this (I'm on a console so I can't use mods). Once one of them dies, the marriage immediately ends. You can kill them both and have them remarry as ghosts, but I'm also trying to send them both to the netherworld and once one of them goes to the netherworld, the marriage between them dissolves once more.

It's just frustrating, because I want Cordelia V and Thiago to appear in the family tree as a deceased married couple, not two unmarried people who had children together.  Can this be done?