Sequence switching with 3 seconds interval

Hi all,
At my home i heat 4 rooms of my house with 7 infrared panels. In every room I have a temperature sensor and i used the HA-thermostat to control the temperature in every room. Soo far so good.

But I noticed that in some case the panels switch on or of at the same time, this causes problems as the energy peak is to high and this disturbed some electronical devices.

So I need to prevent that any of the 7 panels changes states (ON to OFF or OFF to ON) at the same time !

My idea:

Create a list of the HA-thermostat’s and of the related heaters

*> RoomList; > Kitchen, DiningRoom, Serre, Office

*Heaterlist; > IR-Heater-1-Kitchen, IR-Heater-2-Kitchen, IR-Heater-1-Dining-room, IR-Heater-2-Dining-room, IR-Heater-1-Serre, IR-Heater-2-Serre, IR-Heater-Office

The sequence

For all Room ha-thermostat changes
Change state IR-heater-#
IR-heater-# related room == Ha-thermostat room state
Delay = 3 seconds

Next IR-Heater

Can someone help we and guide me into the right direction :blush:
Or is there an even smarter way to solve this problem?