Was fusion between Kaioshins common?

[GreatSaiyaman123]

Chapter: 501 (DBZ 307), P6.7
Context: after Elder Kaioshin explains about the Potara
Kaioshin: “I-I didn’t know about them…”
Elder Kaioshin: “Young people these days really are hopeless…That’s why you’re so weak, despite being a Kaioshin. Here, test it out a little. You and Kibito can use your own Potara…”

Elder said Kaioshin was so weak because he was hopelessly dumb, about the Potara specifically. Does this imply it can common for Kaioshins to merge in order to become stronger in the past?

[Lionel]

It struck me as a consequential last resort that was only to be undertaken under the most dire circumstances such as universal extinction against a threat whom the Kaioshin can't handle. Since the Dragon Balls weren't known of at the time you would be having to sacrifice two of the topmost cardinal deities of that universe in order to acquire the necessary power for overcoming a danger.

Elder Kaioshin may have been aware of it and even seen its usage but I imagine it's a strategy only to be implemented rarely.

[Koitsukai]

I doubt it, they never attempted to do it against Buu or Moro. Unless the buff Kaioshin was actually a couple of kaioshin fused together...

[theherodjl]

Assuming that Beerus valued his survival enough and/or got nagged into action by Whis, the Kaioshin probably didn't need to fuse that often as Beerus would take care of whatever threat was up against them.
Fusion is always a last resort for the heroes and that goes the same for the Kaioshin...which could explain why they forgot about the potara's effects in the first place.

[Peach]

It always striked me as a technique that they were capable of doing, but didn't do much.