Can I add a "OR" on a dependecy? I'm working a on a project that needs to have one of their submodules enable but not both. 

I was wondering if I can have an or statement  in the .info so the user would not enable both submodules.

The Drupal 7 documentation "Writing module .info files (Drupal 7.x)" does not talk about this.
The direct answer to your question (can you use "OR" in an .info file?) has already been provided, but the actual functional outcome you're looking for can be achieved with hook_requirements.  For instance, you might use this code in my_module.install:

function my_module_requirements($phase) {

  $requirements = array();

  if ($phase == 'install') {
      if (module_exists('submodule1') &amp;&amp; module_exists('submodule2')) {
        $requirements['too_many_modules'] = array(
          'title' =&gt; $t('Too many modules'),
          'description' =&gt; t('You may not enable submodule1 and submodule2 simultaneously'),
          'value' =&gt; 'Too many modules',
          'severity' =&gt; REQUIREMENT_ERROR,
        );
      }
      if (!module_exists('submodule1') &amp;&amp; !module_exists('submodule2')) {
        $requirements['not_enough_modules'] = array(
          'title' =&gt; $t('Not enough modules'),
          'description' =&gt; t('You must enable submodule1 or submodule2 (but not both)'),
          'value' =&gt; 'Not enough modules',
          'severity' =&gt; REQUIREMENT_ERROR,
        );
      }
    }

  return $requirements;
}


Further reading