In Blackheart, I can think of a few places where they will have devoted alchemists working towards a common goal.
1) As MoltenDarkness mentioned, the Royal Blackheart Society of Alchemists and Physicians is an excellent choice. To my knowledge, they're going to be set up in Coldforge County in Darkholm Duchy, though I don't think a city has been decided.
2) The Whispering Mother Healing Guild is another option, and they're located in Falkenskiold, in Drakeolm Duchy.
The first guild stated goal is to have a kingdom-wide stretch of guildhalls, and will likely be a better choice for you. The Whispering Mother guild is going to gear towards medicine, from what I understand, and will likely be limited to Drakeolm Duchy.
That being said, if you want to strive and set up your own business, approach a Blackheart Count/Mayor and ask to join whatever settlement they end up leading.
Hope this helps!