Setting Graph Series Value Formulas Based On Other Dependencies?

A line graph is using a data row to plot the line; works fine. The data series ranges have been named for Week1 (H10), Week1_2 (H10:I10), Week1_3 (H10:J10), Week1_4 (H10:K10), Week1_5 (H10:L10), Week1_6 (H10:M10), Week1_7 (H10:N10), ...etc.

This is the data series formula name example to plot the data series from week 1 through week 7; ='Product Plan Q3 Week 7.xlsx'!Q3Wk1_7.

The series name formula Q3Wk1_7 for week 1 through week 7 is =$H$10:$N$10.

When this name is manually entered as a Series Value for the line graph, the graph plots exactly the way it is expected. The same is true if the Series Value is manually modified for some other ranges such as Week 1 through Week 9 (='Product Plan Q3 Week 7.xlsx'!Q3Wk1_9).

My challenge is to enter this Series Value based on the manually entered week number elsewhere; i.e., we're in week 7, the Series Value should be ='Product Plan Q3 Week 7.xlsx'!Q3Wk1_7. I've been trying to use an HLOOKUP table to select the correct Series Value formula based on the week number. The HLOOKUP works fine resulting in selecting the correct formula. I can also Name the range of data I want to graph and copy the name into the Series Value field with successful results. How do I get such a formula or Named range into the Series Value field without type it in? I want to set that Series Value to a range or name without having to select the line to manually enter the value.