Exec SSIS Package Based On A File Existence

I am not sure if we can execute SSIS package using t-sql, but I want to do the following:
Step1. Execute SSIS package1
Step2. Check for the file1.txt in c drive using the below code:
Declare @result int
exec xp_fileexist 'c:file1.txt', @result output
IF (@result = 1) --if file exists exec ssis package
begin
Execute SSIS package2
end

If we can't use t-sql, please let me know how I can do that as part of sql job. Thanks!!