[Freeswitch-users] Custom variable, which will be sent with all events?

hi, is there a way to set a custom variable, which will be sent with all events for a specific uuid? i am using socket outbound and would like to set a custom variable for an inbound call or all orginates, so i can filter this variable. but this variable need to be sent will ALL events, also with dtmf, heartbeat and so on. thanks dennis