Yes,
Homegroup is networking. When you setup you homegroup, use a strong password, one with mixed numbers and upper and lower case letters, and at least one special character.
That said, for your printing, I recommend using a print server (PS) instead of sharing the printer. With a PS, the printing device (printer or AiO) sits on (connects to) your network just like your computers do - either via wireless or by Ethernet cable (or in your case, your router also supports network printing via USB). In this way there are many advantages.
- Better security as no printer sharing is required,
- The printer is not tethered to a "host" computer,
- No "host" computer need be up and running for others to print,
- The printer can be centrally located for easy access to all users,
- All users can print at the same time and PS will sort the print jobs out.
See page 12 of your Belkin router manual for connecting and setting up network printing.