Our libraries in our consortium are frustrated when items from other libraries arrive to fill holds for their patrons and their own copy is sitting on their shelves, making the process look rather inefficient.

What I think might solve this is implementing SirsiDynix's "Trap hold with first item received" feature. Rather than try to explain it myself, I've quoted it from their website below:

"Using the "Trap hold with first item received at pickup library" feature, the system can be configured to allow filling a library user's hold with the first holdable copy of an item received at the pickup library—be it a checked in item or an item in transit. To pre-empt another item currently in transit, the library where another qualifying item is checked in or received must match the library user's pickup library. When the second copy is checked in, the system will check for outstanding holds, including holds that have been flagged to be filled but are not yet Available. If this second copy can fill the hold, it will be trapped to fill the hold and the hold will become available. When the first copy put into transit is received at the pickup library, that copy will either be used to fill other holds or be routed back to the item's owning library.

For example, a very popular title in your library catalog may have numerous copies system-wide. User A places a hold on this title for pickup at Library B. Copy A is then checked in at Library A and is put in transit to Library B to fill User A's hold. Meanwhile, Copy B is checked in at Library B. Copy B would then be made available to fill Library User A's hold, even though Copy A was originally the item to fill User A's hold. When Copy A is eventually received at Library B, it will be put back into transit for shelving at Library A, or be routed to another pickup library to fill another library user's hold. This system behavior allows User A to more quickly check out a copy of this popular title, rather than having to wait for another copy of the same title to arrive at the designated pickup library."

Here is the direct link to the article: https://sirsi.sitehost.iu.edu/Helps/Symphony/Workflows/English/Content/Topics/07-Circulation/Demand_Management_Overvi.htm

The other thing that might help is, if the item actually did start out on the patron's pick-up library's pick list, that the system gives the patron's pick-up library 24 hours to fill the hold with the item from their own collection, rather than filling the hold with an item at another library that is inadvertently checked in while the hold is sitting on the patron's pick-up library's pick list.

(Feel free to split this idea up into two ideas if that's the way I should have done this in the first place.)