Custom Connector - This is exactly the feature you need. It is already done and it supports changing the number of connectors, their location, appearance and so on.
There is way currently to remove some of the connectors (and to add too), but there is no way to specify where it should be positioned. So currently there just five types and that's it - Left, Top, Bottom, Right and Auto. While in the Q2 version you'll have Custom type with Offset point to position it where you need to.
If you're not in a hurry I can suggest you to wait for a month and a half and get the new version. In the meanwhile I can send you preview demo with code and assemblies of the mentioned feature. (just create a private support ticket).
Hope this time frame is ok with you.
All the best,
the Telerik team
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