Use slicer to hide columns based on selection in another pivot table

HI,

I know that tilte is a bit cryptic but I don't know how to say it in a precise manner, so I hope that it'll make more sense if you read below.

My basic setup is a calendar with each day of the year as columns and then a number of of activities in rows. Each activity can have multiple dates.

Based on the approach found at ...excelcampus.com/vba/hide-unhide-columns-slicer-filter. I have used the pivot slicer to enable the users to show/hide months that they find relevant, which is quite practical as there' a lot of scrolling involved for the entire year. However, this only hides columns and shows all actvities in the given months.

What I'm trying to do is to make a slicer with the different activities so that when you select a given activity, only the months that have dates for that activity are shown.

I have made a table that, for each activity, lists which months are relevant. I thought that it could work, to make another pivot table so that when I select a given activity, then the months listed for that acitvity would be passed to the pitvot table that is used for hiding/showing columns. However, I can't make that work.

I've attached my workbook

Do you have any ideas as to how to approach this? I'd be happy to send my setup if that makes it easier to understand :-).

Thanks and take care,

Thor