Logic to sync only new items from Rally to ALM : Delta sync

We have built a one way sync from Rally to ALM.

As per rule, whenever any new Portfolio Item type getting added in Rally, we are creating a new requirement in ALM.

Current problem is: whenever we are using MF Connect to sync, it is resetting the requirements in ALM and discarding all the changes created by user in ALM after sync.

We need to know, is there any way to ensure once a requirement gets created as a new Feature gets added in Rally, it will stop syncing again.

We tried to find any logic like it will sync any Feature from rally which created like 'Yesterday' but couldn't find. Currently it is accepting a hard date. Also, we can't add a new field in Rally to distinguish new and old item as we have to build only 1 way sync - from Rally to ALM.

Can you please help? Please also let us know in case you need more information / clarification regarding this.