Join separate segments under a unique ID

[CarrieASims]

Hi,
I am segmenting coral benthic maps. Often coral colonies can undergo partial mortality - so a single colony (genet/individual) can section into two parts but would still be considered a single genet/individual. Is there a way to join two separate segments under one unique ID?

The only solution I have at the moment is creating a thin segment between the two sections to join them, but this will give an inaccurate area measure.