Merge replication - excluded columns

I have excluded a column from replication. In post snapshot processing, I add this column back on the subscriber and update with a computed value.Even though this column isn't replicated, the updates all go back to the publisher (I can see these in the msmerge_genhistory table on the subscriber and in the publisher). They don't actually change data on the publisher but they do go through the replication processing. This is forcing large amounts of data to go across our WAN. Is there any way for merge replication to 'ignore' the updates to this column?