Harry asked: When bicycles are in groups are they supposed to ride single file or are they allowed to ride side by side?
Whether in a group or not, cyclists must follow the same laws. If they are not unlawfully impeding other traffic, they may ride side by side within the same lane. They are not permitted to ride more than two abreast in the roadway except in bicycle facilities.
s. 316.2065 – Bicycle Regulations
(6) Persons riding bicycles upon a roadway may not ride more than two abreast except on paths or parts of roadways set aside for the exclusive use of bicycles. Persons riding two abreast may not impede traffic when traveling at less than the normal speed of traffic at the time and place and under the conditions then existing and shall ride within a single lane.
See this post about cyclists riding abreast and impeding traffic.