Routing issue with 2 VPN on ASA

Question

Hello,
I am trying to setup a VPN between 3 sites :
site2 and site3 needs to communicate with site1(ASA) :
     site1(ASA)
     |               |
     |               |
site2          site3
         Peer
On site2 / site3 if have multiple peers that want to communicate to site 1 and that can arrive indifferently on site2 or site3 firewall.
All VPNs are UP but there is a routing problem is located on the ASA. Indeed, site2 to site1 communication is ok in both directions. The problem comes from site3.
On site3, incoming packets reach the target on site1 through the VPN, but the answer is sent back through site1/site2 VPN.
Is there a simple way to force the trafic to use the same VPN for responding data ?
Here is a sample of the configuration on the ASA (subnet on site2 and site3 must be left on 'any') :
access-list outside_cryptomap_1 extended permit ip 10.0.0.0 255.255.0.0 any
access-list outside_cryptomap_2 extended permit ip 10.0.0.0 255.255.0.0 any
crypto map my-crypto-map 1 match address outside_cryptomap_1
crypto map my-crypto-map 1 set pfs
crypto map my-crypto-map 1 set peer 90.X.Y.Z
crypto map my-crypto-map 1 set transform-set ESP-AES-256-SHA
crypto map my-crypto-map 1 set security-association lifetime kilobytes 51200
crypto map my-crypto-map 2 match address outside_cryptomap_2
crypto map my-crypto-map 2 set pfs
crypto map my-crypto-map 2 set peer 190.X.Y.Z
crypto map my-crypto-map 2 set transform-set ESP-AES-256-SHA

Answer 1

No, this is not possible, you cannot have overlapping crypto ACLs.
One possible solution might be to apply NAT to the traffic before it enters the tunnel on site3.
But so this requires changing from "any" to one or more specific networks.
hth
Herbert