All together and In parallel

All together adverb - Used of a group whose members acted or were acted upon collectively and when `all' and `together' can be separated by other words.

In parallel and all together are semantically related. In some cases you can use "In parallel" instead an adverb phrase "All together".

All together and in parallel are semantically related. You can use "All together" instead an adverb phrase "In parallel".