Advice request

I'm not sure what to do so thought I'd ask for your advice.

I have 2 hedgehogs regularly visiting the feeder which is fantastic. But now that my resident mama fox gave birth to 3 cubs the feeder is being emptied by the cubs leaving no food for the hedgehogs.

The feeder itself is one of those maze ones but the cubs are so tiny that they go inside, eat, turn around and come out.

I know that the foxes won't harm the hedgehogs (mama fox has been living in harmony with them for a while) but can I deter foxes but not hedgehogs? Foxes hate for example citronella oil. When they were using the area by the back door as a toilet a few drops of the oil stopped them coming - this is far, far away from where the feeder is. 

Can I use the citronella oil in the area near the feeder to stop the foxes but not harm/scare away hedgehogs?

I put obstacles near the entrance to the feeder (with gaps large enough for my spiky friends) but the cubs quickly worked out how to bypass them. 

Or am I worried unnecessarily and a short gap in food supply won't do the hedgehogs any harm. I can only imagine that the cubs will soon become too large to enter the feeder anyway.

Magda