Is it possible to obtain Full Crew achievement without romancing with Triss?

To make possible to gather her for the Kaer Morhen battle, I need to succeed a romance. However, if I do it and I also romance with Yennifer (I want her for my love interest) am I doomed to this threesome scenario? Or can I choose again and decide on one of them again at the castle?

Solution 1:

I got the achievement/trophy (playing on PS4) without even starting Triss' side-quest.

Here is what you need to do:

• Don't start Triss' side-quest until you get the main quests that start with Brothers in Arms.

• Then all you need to do is talk to Triss and ask her to come to Kaer Morhen.

• She will then say that you need to help her first before she can come along with you disregarding the romance choices you will make during her side-quest.

Provided you didn't kill Keira and did all the required quests for the others then you will get the Full Crew achievement.

Solution 2:

If you already romanced Triss I'm pretty sure you have to choose her if you don't want the bad scenario, but I've heard there are a few ways to get her to the Fortress without romancing her; look at option 2 on this guide: http://www.ign.com/wikis/the-witcher-3-wild-hunt/Sex_and_Romance

I've also heard that you can let her go and she shows up anyways letting you get the trophy. Not sure on that though as I haven't beat the game.