How can I run a STDEV on specific cells based on mixed groups?

Question

I have a spreadsheet that has the value of two groups of participants in an experiment
(Group 1 and 2). It looks something like this:

Group..........Value
1...............5
2...............3
1...............7
1...............5
1...............9
2...............1
1...............0
2...............2
2...............4
2...............5

Below I want to create cells that will have the STDEV of the different groups.
E.g. SDGroup1 and SDGroup2

How can I tell Google Sheets to average the values that in the group row have a specific value?

P.S. this is a very simplified snippet, I want to do this for maybe hundreds of rows, and multiple groups, so selecting the cells manually will not do.

Answer 1

D1 cell: =UNIQUE(A2:A)

E2 cell: =STDEV(FILTER(B:B, A:A=D2))

E3 cell: =STDEV(FILTER(B:B, A:A=D3))