Directional radio, tinc and routing

[Novae]

Hi ^^

first my current Situation

Network 1				Network 2
192.168.21.0/24 (re1)			192.168.22.0/24 (re1)
1 WAN (VDSL) (re0)			1 WAN (VDSL) (re0)

there some more Networks (.23/24 .24/24, .25/24) but the networks are not part of the problem ;)
all networks are connected trought TINC in Switch Mode,

Network 1 and Network 2 are in different Buildings, but only 300meters (~0,2miles) away from each other.
So we have installed some directional radio to connect this two networks directly.

now the Question(s)

The directional radio are 2x PowerBeam 5AC 620 one in Bridge mode (192.168.21.254/24) and one in SoHo-Router Mode (192.168.21.253/24 and 192.168.22.254/24).
When i add the SoHo Router IPs at Gateways and add the (static)routes in pfSense all traffic between .22.0/24 and .21.0/24 is routed over the WiFi
(i also disabled the tinc connect on startup for this 2 points)
So that works :)

but… i got in both buildings a telephone system that need to talk to each other... and that doesnt work over the SoHo router...

So my idea was:
Enable the WiFi route for alle devices except the telephone system (.21.151 and .22.151)
Set the route for this 2 devices over TINC
But HOW?!

is that Possible? o.O

or would it be easier to switch the SoHo Router to fully bridged and plug it into (re2) on the .22.0/24 site?
(That would physically be possible)

What would do make more sense?

or it even Possible to set up the Tinc Connection as Backup for the WiFi?
So if we got a bad WiFi connection -> Switch to Tinc?

Best Regards
Novae