It's not technically the same as grappling. When I engulf, my targets get trapped in my body and are treated as being grappled. Normally you're limited in how many creatures you can actively grapple because you normally have only two limbs to use to hold the grapple (in the case of some creatures with improved grab, they can use each limb on a separate grapple, though usually at a penalty). In this case, I'm not using any limbs for the grapple. As long as I have space in my body (enough for one large creature or four medium or small creatures, I should be able to engulf targets.
However, I have noticed a rule in engulf that stipulates that I cannot make a slam attack in a round in which I attempt to engulf. Technically, I think that means I can not make the grapple check to deal damage, so all I can do is get right up next to the hunter. I'll change my actions to reflect that.