Got inspired by these posts so I got an Arduino with a CT clamp switching a solid state rely. This enables my me to run my house supply with a single 5kw Growatt inverter. The CT clamp measure my house supply continuously and when the load increases above 1000W it will switch the Geyser (4KW) off. This circuit is only active during peak solar hours.
It still need to be optimized a bit but works good so far.