superimposing/merging values of two data sets with different time intervals

Hi,
I've tried searching around the net for this problem but haven't found a solution yet - wondering if anyone has any smarts to get around it.

I have two data sets with two different time steps (x-values eg, 3 min intervals and 7 min intervals) with varying corresponding y-values. I want to interpolate + combine those two data sets y-values to form a new superimposed data set with a new time interval of, say, 5mins. Please see attached example.

Would love to get any ideas or headway into this!

Thanks!