Ipsec Tunnel down when one of multi wan down

[badilcan]

we have multi-wan connections wan to opt3 ,
we use default wan to establish ipsec vpn tunnel to our branch offices ,branch offices use pfsense and zyxel 661.
but when one of our other interfaces(opt1,opt2,opt3) down and up , our main pfsense try to establish all ıpsec tunnel again.
Our remote users' connection have had lost connection.
How can I solve that problem ?

Best Regards
Onur .

[cmb]

What does your system log show at the time that happens?