Lagging --
One method to use is with a distribution panel and impedance matching volume controls. I used this in a previous house, two speakers at the patio and two in the kitchen ceiling. Used a Dayton class D amp.
Had a 4 post speaker wall panel that had multiple outputs on the rear. Run speaker connections to the volume control (one for each set of speakers) and then on to the speakers. Set the number of speakers/load at the volume control. Powered all four with a Dayton class D amp.
Am doing the same at the house we just moved to. Using a monoprice 8 pair distribution panel. Feed that with a Aiyima A7 amp.
From the left - distribution panel - Aiyima - amp power - DAC - not seen raspberry Pi
Only the porch speakers wired currently, the kitchen is being renovated starting in a few week so hope to have the ceiling speakers install in the next couple of months. The raspberry runs a spotify connect client (raspotify) so I can run things from my phone (via the LAN) or use RDP to use VLAN to play ripped tunes from the connected USB SSD