HydroSpikes can be set up with multiple plants to one reservoir. Here is a picture of one setup we have. Plants doing pretty well for weeks at a time when on vacation. You also can use an inverted flat garbage lid to place all your plants in it.
When I first set these up (following the instructions on the package), I didn’t see how they would work. But, after a time I noticed the water level in my reservoir bottle beginning to drop. I was amazed. The flow rate is slow, so if you have a very large pot you will need more than one HydroSpike.