I really don't know if this is the right section to ask this question as it deals with both generic routing and VPN/firewalling technologies.
I've simulated and tested the well-known scenario described in this guide:
But when I tried to build three sites connectivity I ran into a limitation saying that "Only one neighbor allowed on point-to-point interfaces" when trying to configure two neibhors on one ASA. Assuming that I would need two interfaces looking outside will complicate the entire design. See the attached diagram showing the connectivity. All routers and ASA firewalls are expected to be in one area 0 and backup radio links should be used as the feasible successor in case of IPSec tunnel failure.
Is there any documented or similar examples? Any ideas how it would be better to design it?
As an afterthought, would I overcome this limitation if add one more OSPF process and then redistribute routes from another routing process similar to this:
router ospf 1
network 192.168.1.0 255.255.255.0 area 0
redistribute ospf 2 metric 100 subnets
router ospf 2
network 192.168.2.0 255.255.255.0 area 0
redistribute ospf 1 metric 100 subnets