What are you doing to those plants? Radiation? Steroids?
Some Phal. just want to be colonies instead of homesteaders. You have found the 'group' Phal while the rest of us are growing staunch individualists. The Keikis that form on the spend bloom stalks grow roots and can be repotted on their own. The keikis (I don't think they are technically keikis) that come off the main stem of the plant never grow their own roots. The plant has just divided. It seems the newer hybrids are doing this more and more.
Thoughts?
Daisy