iphone 6 plus in UK on EE no group message to switch off

Hi

I want to send group messages out - but don't want people to see who else got the messages

There is no 'group off' option [I'm in the UK]

How do I send multiple people the same text [fast and easy] without it going as a group [?]

Also any tips on how best to send the messages

My old phone only let me send a message to 20 people in one go. Can I send to 100 people in one go?

And is there a limit to text size. MY old phone went up to 5 texts max [length for one message - text] any more, then I had to edit words down to be able to send it as a text. Is there a limit on iphone 6. Or could I text 'war in peace' in one text to someone - hmm

Thanks for any and all help