One way to do it is to have any control class necessary register themselves with the owning form, provided the owning form has a particular method, as judged by PemStatus(). So you PemStatus() from myctrl.Init() to see if Thisform has method m_registercontrol. If so, send it a:

Thisform.m_registercontrol(This)

Then m_registercontrol increases the dimensionality of a form property, say r_aoRegisteredObjects, and adds the object to it. It is a simple matter after that to see if a particular object is in your array or not.

Adam