Multi-stage High Side MOSFET driver
On the one hand, I don't for a moment believe that you've drawn your circuit correctly. After all, as long as even one relay is open, no current can flow.

However, let's pretend that what you've asked for is what you want. Then you can replace your relays with MOSFETs, with the gate drive transformer-isolated. The circuit would look something like this for each MOSFET:







simulate this circuit &ndash; Schematic created using CircuitLab

Note that you still have a relay, but it is a very low power unit. Likewise, the transformer is a tiny little audio transformer. You need a source of AC, but you can use a single oscillator to drive all the channels; about 1 KHz should do you. The output of the transformers should be about 5 or 6 volts RMS.  R and C are determined by how fast you need the MOSFET to turn on and off.