Selecting a range variable in different worksheets within same workbook

I am having trouble figuring out how to do the following:

I want to make a range variable ("testrange") that I can use to define a range of non-continuous cells and then use that range variable to select that range of cells in different worksheets within the same workbook.

I tried the below code (simply coloring cells red), but get an error when I try to select "testrange" after moving to the next worksheet.

Sub rangetoworksheets()

Dim testrange As Range

Set testrange = Union(Range("A1:H2"), Range("B6:H6"))

testrange.Select
    With Selection.Interior
        .Pattern = xlSolid
        .PatternColorIndex = xlAutomatic
        .Color = 255
        .TintAndShade = 0
        .PatternTintAndShade = 0
    End With
    
ActiveSheet.Next.Select
    
testrange.Select
'' I get an error on the above line.
    
   With Selection.Interior
        .Pattern = xlSolid
        .PatternColorIndex = xlAutomatic
        .Color = 255
        .TintAndShade = 0
        .PatternTintAndShade = 0
    End With

End Sub

The next worksheet is also supposed to have the same range of cells colored red, but I can only get it to work on the first active sheet.

I would like to avoid having to repeatedly rebuild the range I want selected each time I move to a different worksheet.

I will appreciate any help on this.