Before I change over to SMTP

Dear Sirs,
Forgive the naive question, but before I commit to setting up the 17 Gmail accounts I will need for our webmail team, can you give me some guidance please?
We currently use Horde which is POP3 it’s a very clunky web mail which I’d like to replace with Gmail.
I see there is a fairly lengthy process of changes to make, but am I correct in thinking that your plugin ‘GMAIL SMTP’ will provide all that I need to change over, so all our team can simply use Gmail to access all the mail coming via our web site?
Kind regards
Stephen