I have a site I recently upgraded. The old site had a calendar that created hundreds of pages, on the new site this has been replaced by an events page and those calendar UR
You can do with a few rewrite rules:
RewriteEngine on
RewriteRule ^calendar-for-groups/(.*) /events [R=301,L]
You could use the RedirectMatch directive of mod_alias:
RedirectMatch 301 ^/calendar-for-groups/.*$ http://www.mywebsite.com/events
Or with mod_rewrite:
RewriteRule ^calendar-for-groups/ http://www.mywebsite.com/events [R=301,L]