Odd pairing

Hello all! I just recently added a tiger pistol shrimp to my tank and it paired up with my Hi-fin goby no problem. They have burrows all over the place and it is so fun to watch them interact. What is odd to me though, is that my two scissortail gobies seem to have paired up with the shrimp and the Hi-fin. One of the burrows is right up against the glass, and I've noticed the scissortails in there with the shrimp on numerous occations. They all seem to be happy and share the burrows without a fuss. Is this normal? I've just never seen anything like this before.

 

Interesting since the Sissortail is a dartfish not goby. But since they do like to bury themselves in sand who knows. If there are no arguements then everything should be fine.

 

There have been no arguments so far. They seem to be working together just fine; I've seen the Hi-fin move out of the way a couple times to let the scissortails in. Hopefully the peace remains.