Send a new email to several recipients defined by addressees of another email

[beaky]

I frequently need to send emails to a group of recipients, and am looking for shortcuts.
In the people app, I can very easily set up groups, I can even launch aquamail and send a vcf containing these names. I cannot launch aquamail to send to these names.
But wait, there is a way.... If I have PREVIOUSLY sent to them, I can open my sent folder, find the old email, click on the icon next to the names, and then in a new draft, just paste them in. A small handful of taps, and no tnarscpirtion errors:-) at most I have to do this a couple of times - copying the to and the cc .
What I would like to do (while there seems not to be a proper way of handling groups) is to do the same copy and paste exercise with emails received. Note,  I don't want to reply-all, I want a new topic, that is unlikely to end up mixed with the old thread in another email client in its threaded view.
In the inbox, the ability to click on the header of a received mail and copy the list of addresses automagically does not seem to exist - but does it? I thought I had done it before, but I can't recreate how.
How do I do this....?
(As an aside, I wonder why the Google 'people' app does not offer me the ability to compose an email to members of a group, even in the factory-installed default email client, which still lurks unused on my tablet. I can do loads of other things, but send an email - no. Odd, because I would think this would be the main intent for a set of email addresses).

[Kostya Vasilyev]

AquaMail, since 1.2.5.0, has its own contact picker, which has groups.

You can pick an entire group with a single tap, or expand it and choose individual items.

You can bring up the app's contact picker by using the "human head with a plus sign" icon / button to the left of each address entry field.

[beaky]

AquaMail, since 1.2.5.0, has its own contact picker, which has groups.

You can pick an entire group with a single tap, or expand it and choose individual items.

You can bring up the app's contact picker by using the "human head with a plus sign" icon / button to the left of each address entry field.

Indeed, I can, but it only picks the addresses from emails I have sent. On emails I have received, I see a different head icon in a grey square, with a triangle bottom right. With that, I can add the sender (always singular) to my contacts, or if already there, it opens a window for that contact.
So on messages I have sent, I can select all of the to or cc addresses in the way you describe, but in messages I have received, I cannot so easily copy the to or cc, only the from.
I am using 1.2.5.8.
On reflection, though, I can still use the long-press text select function, and stretch the selection to cover all of the to or cc addresses, copy, then paste into a new draft.
This is very little different to Thunderbird in that respect, so is a valid workaround.
To work, I must have expanded the header to show them all first.