[mothered]

I just realized that I wanted to SE several websites from the same group (ldlc group). Do you think I can still do it or is it common that within the same group they share transaction information to see if people SE them?

There's a central database with that particular group, hence they have the capacity to view Information. I'm not suggesting It will be done, but rather It can be done.

I strongly suggest to take each SE one step at a time.