I ride a Honda Vtwin 500, similar to your Virago in size, era, weight (~400 lb), HP (~50hp), though I have 6 gears. On the 401 I can cruise at 110 kph at 4,200 rpm, while redline is 9,500 rpm. I have no issues with getting to 140 kph if necessary. There is absolutely no problem keeping up with traffic on the highway, and even passing cars.
That being said if you want to ride for many hours a larger bike would cruise at a much lower RPM and be more comfortable. Lower RPM means much less vibration and therefore more overall comfort.
Get a windshield for your Virago and you will be more than able to keep up with your friends.