Just started out with RoundCube, hence:
Can groups of emails be created in Roundcube? If so, how?
Also are there restrictions on how many addresses can be included in a group or how many groups can be created?
Assuming you are using the Elastic skin then in the top left of the Contacts screen you should see the title "Groups" and there are 3 vertical dots, click the dots and a menu appears and there you should see "Add group". Once you have created a group you can drag and drop contacts into it. By default there is no limit to the number of contacts you can put into a group but this can be changed in the config file.