script for adding new domain user to old domain groups

Hi there

We are in the process of an interforest migration and have hit an issue wrt to sid history on groups. I am looking for a script or process to follow to enumerate group membership in old domain, amend output file and add new domain users as members to old domain group.

Or could we simply add new domain group as a member to old domain group?

Remember these are 2 different AD forests with 2-way forest trust with sid history filtering disabled.

Thanks