Two asterisk servers - call routing

Asterisk Asterisk Support
1

Hi,

i have two asterisk server connected via IAX trunk.

First server iax.conf

[gsm] type=peer host=192.168.4.46 secret=secret context=outgoing allow=alaw

Second server iax.conf

[asterisk2]
type=user
host=192.168.2.8
secret=haslo
context=outgoing
trunk=yes
allow=alaw

in extensions.ael(first server):

ifTime (*|sat-sun|*|*)
{
      Dial(IAX2/gsm/${CUT(EXTEN,,3)},30);
      if ("${DIALSTATUS}" = "CONGESTION")
      {
           Dial(${TRUNK_TANIPLUS}/${CUT(EXTEN,,3)},30);
      }
}
else
{                                                     
      Dial(${TRUNK_TANIPLUS}/${CUT(EXTEN,,3)},30);
};

is there better way to fill first trunk on second machine and then, if is fully used, use first?

On this way second server generate many warnings:

WARNING[8037]: app_dial.c:1183 dial_exec_full: Unable to create channel of type 'VGSM' (cause 34 - Circuit/channel congestion)

Greetings