extensions_additional.conf:

[outrt-10] ; Mexico
include => outrt-10-custom
exten => _0052.,1,Macro(user-callerid,LIMIT,)
exten => _0052.,n,Set(MOHCLASS=${IF($["${MOHCLASS}"=""]?default:${MOHCLASS})})
exten => _0052.,n,Set(_NODEST=)
exten => _0052.,n,Gosub(sub-record-check,s,1(out,${EXTEN},))
exten => _0052.,n,Macro(dialout-trunk,1,${EXTEN},)
exten => _0052.,n,Macro(outisbusy,)

extensions_custom.conf:

[outrt-10-custom] ; Mexico
exten => _0052.,1,Macro(user-callerid,LIMIT,)
exten => _0052.,n,Noop("We are In the CONTEXT!!!")
exten => _0052.,n,Set(MOHCLASS=${IF($["${MOHCLASS}"=""]?default:${MOHCLASS})})
exten => _0052.,n,Set(_NODEST=)
exten => _0052.,n,Gosub(sub-record-check,s,1(out,${EXTEN},))
exten => _0052.,n,Macro(dialout-trunk,1,${EXTEN},)
exten => _0052.,n,Macro(outisbusy,)