Ask Mr. Smarty Plants

Ampelopsis arborea (peppervine) is a member of the Vitaceae or grape family. We could find no indication that it is poisonous; the page on it in our Native Plant Database says:

"Fruit fleshy, up to 5/8 inch in diameter, black and shiny when ripe, inedible."

But, in the forum Dave's Garden on peppervine, we found one comment (the last one) as follows: 

"I ate a lot of the berries this summer. They are related to grapes, and are sweet with a slight black pepper taste. Still a very beautiful plant.
Wildlife like birds, raccoons and so forth are very fond of these. They eat most before I get a chance."

Since you have already reduced the fruits to juice, you might try taking a cautious taste of it to see if the few peppervine berries have influenced the taste, and make your decision. You know you're going to have to add a lot of sugar and pectin to the juice anyway, since you are dealing with wild grapes, so the taste, if there is any, will probably not affect your jelly at all. However, if it will make you feel any better, we found a Florida Plants Online website on Poisonous Plants, including one list specifically of poisonous plants of Florida.  You can give that a look, and if neither the scientific name nor the common name appear, we think your jelly is safe.

From our Native Plant Image Gallery:

Ampelopsis arborea

Ampelopsis arborea

Ampelopsis arborea

Ampelopsis arborea