Extract from the Amp user manual. I’ve highlighted the relevant info. you need…

Make sure your speakers are compatible with Amp:

• Your speakers’ power rating should be at least 125W for 8 ohm speakers, and at least 200W for 4 ohm speakers. Do not connect speakers rated at less than 4 ohm.
• Amp can drive speakers with nominal impedance above 4 ohms. Two pairs of 8 ohm speakers wired in parallel are also supported. Don’t wire your speakers in series because it will result in poor sound quality.

If your outside wire has four conductors then you could wire both outside speakers to the amp, if they and the inside ones are 8 Ohms.

If there are only two conductors in your wire that won’t work. You could wire on or the other outside speaker to the Amp but it would only play sound from the channel it is connected to.

I a have 6 outdoor nonSonos speakers, that I want to connect to a Sonos amp. 
 

Which would be the ideal setting, 1 or 2 amps to drive the 3 pairs of speakers as a single system.

Two Amps, with one pair to one and the other two pair to the other.

You might consider an impedance matching speaker controller that would let you hook all three to one Amp but might limit your maximum volume.

Another option is a Sonos Port hooked to a multi-channel amplifier to run all three pairs.

Tku, will try the 2 amp option

i’m guessing tha the 2 amps can be treated as one device??

jeaj

You can Group them and for the most part they will stay Grouped but can split and need re-Grouped if power fails.

Once grouped they play the same audio stream but have a Group plus individual volume controls so you can level-match your speakers.