Constraints between radial and axial holes

I'm making the transition from MDT6 to Inventor, and I'm having some difficulty with constraints in Inventor. Specifically, I've got a pipe with a radial hole about halfway down its length and a circular flange that fits onto the end of the pipe that has an axial bolt pattern around its periphery. I want to make sure that when the flange is fitted onto the end of the pipe, one of bolt holes is lined up with the radial hole in the pipe. Put it another way, the radial hole should be top dead center w.r.t the end view of the pipe, and when the flange is fitted onto the end of the pipe, one of the bolt holes is also top dead center.

Could someone walk me through this? I'm having to unlearn MDT6, so I may be overlooking something that's obvious in Inventor (like how to make a radial hole on a cylindrical surface ). Thanks in advance for any help.