Table Header in Index to link to cell

Hi, I have a formal that pulls the company names from a table, where a specified field equals yes.

=IFERROR(INDEX(Table2[Company], SMALL(IF(Table2[Asbestos]="Yes", ROW(Table2[Asbestos])-ROW('Approved Suppliers'!A$2)+1), ROWS('Approved Suppliers'!A$2:'Approved Suppliers'!A2))),"")

That is then pulled down the page and seems to work quite happily. However I would need to have multiple versions of this formula to display each category. I need to be able to select the Column header in Table2 dynamically. For example in A1 would be a drop down menu containing 5 categories, the selection from A1 would then be within 'Table2[A1]'. I've tried to match the contents, perform a lookup, but really all i want to do is literally put the contents of A1 within the #Header choice. i.e

=IFERROR(INDEX(Table2[Company], SMALL(IF(Table2[A1]="Yes", ROW(Table2[A1])-ROW('Approved Suppliers'!A$2)+1), ROWS('Approved Suppliers'!A$2:'Approved Suppliers'!A2))),"")

Thanks, i think that has attached ok!

Tony I managed to figure it out! Thanks very much though!

=IFERROR(INDEX(Table2[Company], SMALL(IF(INDEX(Table2,,MATCH($A$1, Table2[#Headers],0))="Yes", ROW(INDEX(Table2,,MATCH($A$1, Table2[#Headers],0)))-ROW('Approved Suppliers'!B$2)+1), ROWS('Approved Suppliers'!A$2:'Approved Suppliers'!A2))),"")

Thats the part that I had to put it:

INDEX(Table2,,MATCH($A$1, Table2[#Headers],0))