Very similar question on the pbo forum recently:
From the looks of the SR161 you're SOL without some additional hardware
. I also note that it outputs rs232
and there's some warning blurb about it not being compatible with (rs422) raymarine
e series, although it will doubtless "work".
Cheapest solution (as mentioned in the thread referenced above) is to acquire a cheap
not usb ouput: same caveats re: 232 vs 422 as ever apply) and 5v power supply. This gives you the additional benefit of being able to have gps to the vhf with the plotter and AIS off.
Multiplexers aren't cheap but they'll do what you want. You'd want something that enables you to filter data to prevent the AIS sentences swamping the 4800 baud line to the VHF. You can knock up a dodgy homebrew one from something like a raspberry pi (or a laptop) but if you're asking this question in the first place I'd suggest you avoid that route
If you're buying
a transponder anyway you could look for one which incorporates a multiplexer. I believe the raymarine
units do (though they're expensive). The XB-8000's 4800 baud line appears to be (do confirm this) input only: if so, that's not going to get your GPS data to the VHF.
Do consider what you don't mind having to have switched on to get GPS data to the VHF. I rarely switch on my AIS, only sometimes have the plotter on, but pretty much always want GPS on the VHF "just in case".
The cheap GPS puck
solution has a lot to be said for it (not least, cost) but can be a bit of a faff with cutting the cables
and hooking up suitable power.