Hi  T Ketaki Debadarshini,
You can achieve this by using following code
In Python
from lxml import etree
@api.model
def fields_view_get(self, view_id='you_form_view_id', view_type='form', toolbar=False, submenu=False):
    res = super(ClassName, self).fields_view_get(view_id=view_id, view_type=view_type, toolbar=toolbar,
                                                  submenu=submenu)
    doc = etree.XML(res['arch'])
    if self.env.user.has_group('group1'):
        for node in doc.xpath("//field[@name='field1']"):
            node.set('modifiers', '{"readonly": true}')
        for node in doc.xpath("//field[@name='field2']"):
            node.set('modifiers', '{"readonly": true}')
    elif self.env.user.has_group('group2'):
        for node in doc.xpath("//field[@name='field2']"):
            node.set('modifiers', '{"readonly": true}')
        for node in doc.xpath("//field[@name='field3']"):
            node.set('modifiers', '{"readonly": true}')
    res['arch'] = etree.tostring(doc)
    return res