How to exclude the results based on some templates in Solr/Suggest search?

Question

I have a scenario that, I want to exclude some templates(Items that are based on these templates are need to be excluded) from solr Suggestion/autocomplete results.

I did set a context field as _template.

<!-- Solr Auto Suggest starts -->
    <searchComponent name="suggest" class="solr.SuggestComponent">
    <lst name="suggester">
      <str name="name">default</str>
      <str name="lookupImpl">AnalyzingInfixLookupFactory</str>
      <str name="dictionaryImpl">DocumentDictionaryFactory</str>
      <str name="field">_name</str>
      <str name="contextField">_template</str>
      <str name="suggestAnalyzerFieldType">text_general</str>
      <str name="buildOnStartup">true</str>
    </lst>
  </searchComponent>

In code, I passed a template ID and I'm getting results based on that template.

But now, I need to remove the result items based on some template ID's(multi-list of excluding templates). How I can achieve this? Any help on this.

my code:

public static List<string> GetSuggestions(IProviderSearchContext context, string term, ID template, int numberResults)
        {
            var suggestedList = new List<string>();
            SolrSuggestQuery query = term;
            var options = new SuggestHandlerQueryOptions
            {
                Parameters = new SuggestParameters
                {
                    Count = numberResults
                }
            };

            if (!template.IsNull)
            {
                options.Parameters.ContextFilterQuery = template.Guid.ToString("N");
            }

            var result = context.Suggest(query, options);
            suggestedList = result.Suggestions["default"].Suggestions.Select(a => a.Term).ToList();
            return suggestedList;
        }

or Do I need to add a new field to the solrconfig.xml(sitecore_master_index) file? if so, please attach an example for this?