Unfortunately, this is not possible. No matter where you go, jellies can only be fought in areas where cannons are not able to be set up. So you will have to find another way to fight them quickly.  To go more in-depth, in the catacombs of Kourend, it is impossible to set up a cannon. Warped jellies only live there, so you can not use one. If you want to attack multiple at a time, you are going to have to use ancient magic here. It is a multi combat zone, so that works. The Femennik Slayer Dungeon is where the regular version of jellies is found. Here, too, it is not allowed to use a cannon. Even more so, it is a single combat zone. This means you can only fight one jelly at a time. So you will not be able to use ancient magic here, and you will need to fight them one by one.  Jellies are not found anywhere else in Old School Runescape. So you will have to fight them in these two spots. There also is no alternative to regular or warped jellies that you can kill instead of them when you are on a slayer task. In short, there is no way to cannon jellies, but if you want to attack multiple at a time and do your task faster, you should use ice burst or ice barrage in the catacombs of Kourend, where it is a multi-zone.