Zoom in within subplot

Is it possible to insert a zoom in plot within subplots ?
Below is part of 3x2 subplot:

gmt subplot set 2,1

gmt psbasemap -R$border -Bpa1Hf1h -Bsa1K -BS
awk ‘{print $1, $4}’ $file | gmt plot -W0.75p,red -t40 -BsWne -Byg2 -Bx+l"epoch"

This what I try to reduce the range to include the zoom in parts of the above plot:
gmt basemap -R$boarder_small_section -JX1i/0.5i -X2i -Y3i
awk ‘{print $1, $4}’ $file | gmt plot -W0.75p,blue -BsWne -Byg2

But it did not work

If I understand you correctly you want an inset in a subplot panel, so why not use gmt inset?
Also, unrelated to your question, but

awk ‘{print $1, $4}’ $file | gmt plot -W0.75p,red -t40 -BsWne -Byg2 -Bx+l"epoch"

might be faster and cleaner if done as

gmt plot $file -i0,3 -W0.75p,red -t40 -BsWne -Byg2 -Bx+l"epoch"

Yes, thanks. I am using gmt inset then. I am trying to inset within one of the 3x2 subplots ( at the position set 2,1) . When I use the inset command below within subplot set 2,1
gmt inset begin -DjBL+w1.5c+o1.25
gmt psbasemap -Rsmall_boarder -JX$scale -Bwesn
gmt plot $file i0,3 -W0.75p,blue -t40 -BsWne -Byg2 -Bx+l"Hours"
gmt inset end

This does not fit exactly inside the subplot set 2,1. I need to fiddle with -D option to fit it
Did I use the command correct ?

Fitting exactly depends on your choice for -J inside that area. I think you could do -JX? to have inset figure it out.