The simplest way to get what you want is to get any receiver having an "Speaker A and B" switch on the front panel. It can be a 5.1 receiver if that's all you need for your main system. This is a very common feature on almost every receiver.
Speakers "A" would be the main (5.1 or 7.1) speaker set and the "B" speakers would be an optional stereo pair, which would be the ones on your deck.
A 5.1 receiver with this common feature is the simplest and most economical way to get into tis hobby and will suit your needs
Both sets would be playing the same source at the same time but that's what you said you wanted.
Now, if you wanted independent source control for both sets of speakers, then you get involved with that zone stuff but it will add to te complexity and cost.
As for brands, any of the mainsream brands are good: Denon, Marantz, Yamaha, Onkyo, or any of the other major brands you'll see mentoined in other posts on this site. You did read some other posts before posting your question, didn't you?