By design, devices on a ZigBee negotiate the route of their connection without user interaction. Using an XBee, I've watched as ZigBee end devices (which cannot act as routers themselves) change their route through one repeater, then a different repeater, and then back to the first repeater. As I understand it, which repeater an end device connects through is determined mainly by the signal strength, relative to that of other nearby repeaters.
So other than making sure incompatible repeaters are distant enough, there's no way to control which repeater (on the same ZigBee network) your Xiaomi / Aqara devices (or any end other devices) will route through.
Also, when I say "incompatible" repeaters, it's not always just because they get "impatient" waiting for Xiaomi / Aqara devices to check in. I have witnessed and read about a host of other issues such as difficulty during pairing, devices never getting past the initialization stage of pairing, and also messages not being sent through to the hub.
Bottom line, you want to make sure there's no way your Xiaomi / Aqara devices will connect through an incompatible repeater. This can be accomplished in three ways:
- Don't use any incompatible repeaters at all.
- Make sure incompatible repeaters are distant enough that Xiaomi / Aqara devices don't route through them. Only an XBee or ZigBee sniffer can help verify this.
- "Sandbox" your Xiaomi / Aqara devices on a different hub (e.g., a second Hubitat, or another home automation solution that works with Xiaomi / Aqara devices - but preferably not a SmartThings hub because too much functionality can be lost)