Changing NetMask of an already discovered network

Dear Sirs,-

We are currently evaluating OpManager and so far it is very impressive.

We have already added and configured quite a large number of devices, by manually adding them.

Only now are we starting to look into "Networks", and have quickly discovered that one of our main networks was already discovered, but is registered with a wrong NetMask.

This network contains the bulk of our manually added devices, which we would very much like to avoid loosing.

Is there a way to change the NetMask on a network, without deleting and creating anew, thereby loosing all the devices (and the huge efforts already put into configuring them) in that network?

Any workaround/trick or suggestion for radical surgery would be highly appreciated.

Thank You and Best Regards,-

Thomas