You could pre-populate the repeater
there is an example here https://gist.github.com/joshuacerbito/3968bf9eaacd44a64c05075afab84697
there is another example here https://gist.github.com/theJasonJones/7061b8020e43a114756214e20c4d0ed9
Note that the second example uses field keys, field keys must be used when doing this.
