Modeling should offer a Replace function.
That Replace function would be used to replace a model by another one, or shared model instances by another model. Position relative to the designated source model and the designated destination model should be used to replace properly in the 3D space the source by the destination.
This Replace function is not the same as Reintegrate. Replace would change the destinations SysID while Reintegrate keep it unchanged.
If you'd like a mature, flexible, and supported solution, you could check out AI Replace Part, which is one of the many functions of AI DesignMAX from AI MAXTools.
Here's a video of it in action: http://www.youtube.com/watch?v=9d8DHb_Xvdo
More demo videos can be found on our website as well:
I'd be glad to answer any questions you have, including getting you set up for a free, no-obligation trial if you're interested.