Squid.conf

I have configure squid in linux.
In the squid.conf file i have to give time restrictions.For a single interval of time the squid works perfectly.
How to give time for multiple interval of timings

for .e.g
acl n123 time 11:00-12:00

the above thing is working

but
acl n123 time 11:00-12:00 14:00-16:00
the above thing is not working..
how to overcome this

thanks in advance
regards
#nanda