I am having difficulty creating an autofill formula.

The first tab of my file is called "By Room" and I would like to link exactly every 9th cell down the sheet (starting with B7 and going forward, B16, B25, B34, B43 etc.) to the second tab, called "Ceilings" into every cell without gaps, starting with A7, A8, A9 etc.

I have done the first 50 as separate links:

The formula in A7 reads: ='By Room'!$B$7

The formula in A8 reads: ='By Room'!$B$16

The formula in A9 reads: ='By Room'!$B$25

etc.

I would like to auto complete this but if I highlight the links already created and drag down the right bottom corner of the cell it just repeats the same links over and over (i.e. it doesn't recognise the pattern that the cell number is increasing by 9 every time).

Any help would be appreciated. The "By Room" tab has 1899 rows so this could take a long time! I think the =INDIRECT formula might be the way forward but I'm not having any luck working this out!