Yes it is,
But depending on your unix skills, it might be complicated. Basically, you need to do a ssh tunnel between you and your remote client and then put a client application to rebroadcast the signal on the other network.
Here is a link that explains how to do it:
BTW, be aware of 2 things
Everyone on the network will see your library in iTunes.
I busted my ISP cap often doing this (listening to music a work all day).