You can do this with one slicer by using a disconnected date + an unpivoted bridge and a tiny rules table.
How
SlicerDate
table (for the slicer).Date1..Date4
into BridgeDates[FactKey, Date, Role, Tower]
.DateRules
mapping which Roles are valid per Month (and per Tower when needed).SlicerDate[Date] -> BridgeDates[Date]
, BridgeDates[FactKey] -> Fact[ID]
, DateRules -> BridgeDates
(Month/Tower).Now Jan–Mar uses Date1, Apr–Jul Date1/2, Aug–Sep Date1/2/3/4, and it respects the selected Tower.
If this helped, I’d really appreciate a like — thanks!