Exclude subnet from site to site ipsec?

[beedix]

I've setup a site to site with pfsense on both ends.  I want ALL internet traffic at site A to appear to be coming from site B.  But I don't want site A's private network to be routed over ipsec (it needs to stay over at site A).  Site A consists of 10.66.0.0/24 which is VPN connected back to site B.  Site A is complex and has other non-ipsec networks that need to be accessible (10.0.0.0/8) without ipsec.

I followed this:
https://doc.pfsense.org/index.php/Routing_internet_traffic_through_a_site-to-site_IPsec_tunnel

Now i'm trying to determine how to keep 10.0.0.0/8 non internet traffic from being sent to Site B.