diff --git a/Phys/B2KShh/job/selection.py b/Phys/B2KShh/job/selection.py
index a8e927b..69bcf26 100644
--- a/Phys/B2KShh/job/selection.py
+++ b/Phys/B2KShh/job/selection.py
@@ -40,7 +40,7 @@
 
 
 def truth_match_string(source, hypo):
-	string  = ''
+	string  = '('
 	mother = 'MOTHER'
 	b_id = truth_match['Lb']
 	if 'Lc' in source:
@@ -50,29 +50,34 @@
 	for h in ['h1', 'h2', 'KS']:
 		string += ' && %s_TRUEID == %s' % (h, truth_match[hypos[hypo][h]])
 		string += ' && %s_%s_TRUEID == %s' % (h, mother, b_id)
+	string += ')'
 	return string
 
 
-sel_strings = {
-	'L0'           : '(L0HadronDecision_TOS || L0Global_TIS)',
-	'HLT1'         : 'Hlt1TrackAllL0Decision_TOS',
-	'2011'         : '(runNumber <= %s)' % end2011,
-	'HLT2-2011'    : '((Hlt2Topo2BodyBBDTDecision_TOS || Hlt2Topo3BodyBBDTDecision_TOS || Hlt2Topo4BodyBBDTDecision_TOS) || (Hlt2Topo2BodySimpleDecision_TOS || Hlt2Topo3BodySimpleDecision_TOS || Hlt2Topo4BodySimpleDecision_TOS))',
-	'2012pre-june' : '(runNumber > %s && runNumber <= %s)' % (end2011, endjune),
-	'2012post-june': '(runNumber > %s)' % endjune,
-	'HLT2-2012'    : '(Hlt2Topo2BodyBBDTDecision_TOS || Hlt2Topo3BodyBBDTDecision_TOS || Hlt2Topo4BodyBBDTDecision_TOS)',
-}
-
-sel_strings['Trigger'] = ' && '.join([sel_strings['L0'], sel_strings['HLT1'], sel_strings['HLT2-2011']])
-sel_strings['Trigger'] += ' && '
-if 'MC_2011' in source:
-	sel_strings['Trigger'] += sel_strings['HLT2-2011']
-elif 'MC_2012' in source:
-	sel_strings['Trigger'] += sel_strings['HLT2-2012']
-elif not 'MC' in source:
-	pass
-else:
-	raise Exception('DANGER: problem with file name parsing and trigger conditions!')
+def make_sel_trings(source, recotree):
+	sel_strings = {
+		'L0'           : '(L0HadronDecision_TOS || L0Global_TIS)',
+		'HLT1'         : 'Hlt1TrackAllL0Decision_TOS',
+		'2011'         : '(runNumber <= %s)' % end2011,
+		'HLT2-2011'    : '((Hlt2Topo2BodyBBDTDecision_TOS || Hlt2Topo3BodyBBDTDecision_TOS || Hlt2Topo4BodyBBDTDecision_TOS) || (Hlt2Topo2BodySimpleDecision_TOS || Hlt2Topo3BodySimpleDecision_TOS || Hlt2Topo4BodySimpleDecision_TOS))',
+		'2012pre-june' : '(runNumber > %s && runNumber <= %s)' % (end2011, endjune),
+		'2012post-june': '(runNumber > %s)' % endjune,
+		'HLT2-2012'    : '(Hlt2Topo2BodyBBDTDecision_TOS || Hlt2Topo3BodyBBDTDecision_TOS || Hlt2Topo4BodyBBDTDecision_TOS)',
+	}
+	
+	sel_strings['Trigger'] = ' && '.join([sel_strings['L0'], sel_strings['HLT1'], sel_strings['HLT2-2011']])
+	sel_strings['Trigger'] += ' && '
+	if 'MC_2011' in source:
+		sel_strings['Trigger'] += sel_strings['HLT2-2011']
+	elif 'MC_2012' in source:
+		sel_strings['Trigger'] += sel_strings['HLT2-2012']
+	elif not 'MC' in source:
+		pass
+	else:
+		raise Exception('DANGER: problem with file name parsing and trigger conditions!')
+	
+	sel_strings['TruthMatch'] = truth_match_string(source, recotree)
+	return sel_strings
 
 
 def getall(d, basepath="/"):
@@ -104,7 +109,23 @@
 	print "\tSource file not in target directory, I'll bring it along..."
 	os.system('cp %s %s' % (source_path + source, target_path + source))
 
-infile = r.TFile(target_path + source, 'read')
+
+def find_input(target_path, source, sel_names):
+	"""
+	If some selections were already performed,
+	use the selected sample as input!
+	"""
+	infile_name = target_path + source
+	available_files = os.listdir(target_path)
+	for i in range(len(sel_names)):
+		sel_subset = sel_names[:i+1]
+		for f in available_files:
+			if f == source.split('.')[0] + '_' + '_'.join(sel_subset) + '.root':
+				infile_name = target_path + f
+	return infile_name
+
+
+infile = r.TFile(find_input(target_path, source, sel_names), 'read')
 trees = []
 
 for k, o in getall(infile):
@@ -127,6 +148,7 @@
 		print '\tMaking directory %s ...' % t.location
 		outfile.mkdir(t.location, t.location)
 	outfile.cd(t.location)
+	sel_strings = make_sel_strings(source, t.GetName())
 	t.cptree = t.tree.CopyTree(' && '.join([sel_strings[sel_name] for sel_name in sel_names]))
 	n_new, n_old = t.cptree.GetEntriesFast(), t.tree.GetEntriesFast()
 	print '\t Copying {0}/{1} tree: {2:.1%} out of {3} events selected...'.format(t.location, t.tree.GetName(), n_new / n_old, n_old)