vhdl-align-same-indent

vhdl-align-same-indent is a variable defined in `vhdl-mode.el'.
Its value is

t

Documentation:
Non-nil means align blocks with same indent separately.
When a region or the entire buffer is aligned, the code is divided into
blocks of same indent which are aligned separately (except for argument/port
lists). This gives nicer alignment in most cases.
Option `vhdl-align-groups' still applies within these blocks.

You can customize this variable.