Is this a normal mode of operation?

I'm wondering if the way that I am running the xinetd server is using a 
feature or programing accident. I didn't find any info or examples where 
others are doing the same thing.

I am setting up my config file to all to service id's to both use the same 
port. One service id restricts the incoming connection addresses to range A 
while the other service id restricts them to range B. Neither range overlaps. 
Both services use the same protocol, TCP. It seems to work OK this way but is 
this and intended mode of operation by the designers? In other words, is it 
safe to assume that it will still work this way on the next revision of the 
program? Here are my two services in question:

# default: on
# description: Qmail SMTP service for delivering and receiving mail via \
#	the SMTP protocol. Provides local service with relaying.
service smtp
{
  disable                  = no
  id                           = smtp-loc
  port                       = 25
  only_from             = 192.168.0.0/16 127.0.0.1
  socket_type         = stream
  protocol                = tcp
  wait                      = no
  env                       = RELAYCLIENT=
  passenv               =
  user                      = qmaild
  flags                     = NOLIBWRAP
  server                  = /var/qmail/bin/tcp-env
  server_args         = -R /var/qmail/bin/qmail-smtpd
  log_on_success  = HOST DURATION PID
  log_on_failure      = HOST
  nice                      = 0
  instances             = 60
  cps                       = 25 5
  rlimit_as               = 2M
}

# default: on
# description: Qmail SMTP service for delivering and receiving mail via \
#	the SMTP protocol. Provide public service with relaying denied.
service smtp
{
  disable	              = no
  id                         = smtp-pub
  port                      = 25
  no_access          = 192.168.0.0/16 127.0.0.1
  socket_type	     = stream
  protocol               = tcp
  wait                     = no
  env                      =
  passenv              =
  user                     = qmaild
  flags                     = NOLIBWRAP
  server                  = /var/qmail/bin/tcp-env
  server_args         = -R /var/qmail/bin/qmail-smtpd
  log_on_success  = HOST DURATION PID
  log_on_failure      = HOST
  nice                      = 0
  instances             = 60
  cps                       = 25 5
  rlimit_as               = 2M
}

Thanks for any comments, opinions, pointers, etc.

-Tony Thedford

-- 
Of all men's miseries, the bitterest is this:
to know so much and have control over nothing.
		-- Herodotus