Yes. The chown command can do what you want (man chown
and look at the "--from" and "-R" options).
As an example, pretend you have a directory that contains all the files you need to change named /home/projects/projB (which includes subdirectories) and that you want to change files owned by "groupa" to "alphag". This command should
Do not run this on your important files until you have tested it first.
chown --from=:groupA -R :alphag /home/projects/projB/*