You can scan for duplicate contacts and then merge several duplicate contacts at the same time
Steps
Select My Apps
Select Contacts
Select More Options
A dropdown menu appears
Select Merge Contacts
You arrive on the Merge Contacts page
Select Scan for duplicate contacts
Makerble detects sets of contacts with matching names and displays
When the contact was created
Who created the contact
Use the checkbox to select which sets of contacts you want to merge
Press Merge selected contacts
The merging will take place in the background