We are using two Separate bug tracking tools (one for the core product and one for customisations). We want to merge them together because
1) we are finding that our customers need fixes before our core dept gets them merged into the core product
Answer: Using Business Rule Requirement it can be resolved - (Core Product Rule 1 & 3 matches with customization on #1). if we do this all the rules will be covered and provide this Excel to Client that it has been verified in this Product release version 1.0.2
2) many bugs are fixed in the core product and our customers have not or choose not to upgrade. Often they don't know which build has the fix.
Answer: Whenever Product release has happened the excel should be sent to clients and which should have the bug status of deferred means that it will be taken care in next version upon you confirmation in the logic or functional flow etc... this makes the customer to confirm from their side to do quality deliverables from us.
3) there is duplicate effort in both departments
Single excel to keep hyperlink on first worksheet of Core Product BR's # and click will navigate to second worksheet of customization rules 1, 2, 3... time will be less...on verification
You may get client appreciation too ....