Variable time delay?

I recorded a large orchestra and choir. One of the tracks is of a bagpipe, with a radio mic, walking up the aisle “into the distance”.

The problem is, that as he gets further away from the main pair, the delay between the main pair and the radio mic increases.

Any suggestions as to how I would be able to synchronise the bagpipe with the main pair until it “disappears”? Is there a variable time delay capability that I could use?