Sending an A/B test email in a multi-flow email campaign

Hi!
i have a rather complex marketing campaign on my hands and i don't know how best to approach it
my sales team wants to send an email promo to several groups of our customers at once + to test 3 different email texts on 1 of the groups (personal customers)

normally i would use the old smart campaign (send email), not the new one (email blast) and add choices in the flow:
if lead in list 1 - send email 1
if lead in list 2 - send email 2
....
if lead in list N - send email N

but i'm not sure how best to squeeze in the A/B test here

can i somehow add an A/B test just for email 1 which would be send to some part of my group 1?
how best to do it? will it affect the other groups i select for my campaign?

here i need to say that our database is full of duplicates that's why i always set up a flow with several emails in 1 campaign - just to make sure 1 lead does not somehow receive several emails when he shouldn't

it is wise in my case to try to attempt to use A/B test at all? i'm worried that it may somehow send several emails to my duplicate records