Yes. It's possible, go to the accounting

In it's configuration there is the option taxes. 

Just create 3 type of taxes for GST.

1) IGST

2)SGST

3)CGST

Give the % of each.

Give a example here for luxury tax of 28% 

In this case we create the tax like this

IGST @ 28%

In the form we give .28%

CGST AND SGST are @ 14% each.

We give in the form 0.14%

This is the simple method to calculate GST in Indian accounting system.

Thank you