IS and "From Room parameter"

[Electric Flute]

IS sums all the identical types of DWs in the schedule, but it breaks the sum if the IS contain Zone names (From Room parameter)
I would like to create a DW IS which contains all the different zone names for a group of identical D/Ws.

Like e.g.:
ID:D1 - Quantity:3 - From Room: Kitchen, Living room, bathroom

Not like e.g.:
ID: D1 - Quantity:1 -From Room: Kitchen
ID: D1 - Quantity:1 -From Room: Living Room
ID: D1 - Quantity:1 -From Room: Bathroom


I hope I was clear. Is it possible??
Thanks.
AC10 Win XP