Another solution.
This is maybe easier for people not familiar with BP that much. This solution was suggested by my colleague.
The idea is, that we replace SEMICOLON with new line feed, so we get comma separated values for each entry on separate row. Then you save the resulting string to a file, so the file looks like
last name, first name, email@mail.com
last name2, first name2, mail2@mail.com
last name3, first name3, email3@mail.com
Then, you can use Get CSV Text As Collection action from Utility - File Management object and load the file, ending up with nice collection you need.