What happens if you place shift a place with a link to a place into that Demi-Plane?

[Senko]

I recently stumbled across a spell that shifts a location to another plane and it got me thinking if you created a greater Demi-Plane with a link to a place what would happen if you moved that place into the Demi-Plane?

For example if a Demi-Plane had a link to a Grove and you moved the grove into the future Demi-Plane would the portal to the plane remain behind, youd wind up with 2 linked spots on that Demi-Plane, it'd explode, something else?

[Rajnish Umbra, Shadow Caller]

What's the spell?

Either way, the easiest rule would be that you just get two linked points on the same plane.

Having it explode or turned into a Klein Demiplane seems like an overreaction.

[avr]

Or that the interplanar link would become inactive as long as both ends were on the same plane.

[Senko]

Annoyingly I've never been able to relocate the spell which is part of why I'm posting here in case someone recognizes it. Still inactive or linked but safe promsing.